Tutorials/Catalyses: Difference between revisions

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→Block replacements: Mentioned that a supporting block can work even if a fishhook doesn't work
Rearranged things and added more catalyses
Line 13: Line 13:


* ''Stable catalyst'': a catalyst which is a still life. Most catalyses are of this form. In this tutorial we will only focus on stable catalyses, as periodic catalyses are as of now quite underdeveloped.
* ''Stable catalyst'': a catalyst which is a still life. Most catalyses are of this form. In this tutorial we will only focus on stable catalyses, as periodic catalyses are as of now quite underdeveloped.
* ''Periodic catalyst'': a catalyst which is an [[oscillator]]. These are generally considered inferior to stable catalyses because they usually only work in a fraction of the generations as a stable catalyst, since they usually only work in one [[phase]] of the periodic catalyse.
* ''Periodic catalyst'': a catalyst which is an [[oscillator]]. These are generally considered inferior to stable catalyses because they usually only work in a fraction of the generations as a stable catalyst, since they usually only work in one [[phase]] of the periodic catalyst.
* ''Transparent catalyst'' or ''transparent object'': an object which is destroyed completely (all of its cells being off at the same time) then restored (in the same position and with the same orientation)
* ''Pseudo-transparent catalyst'': a catalyst that loses all of its cells but not at the same time (i.e. for each generation, at least one of its cells is alive)
* ''Recovery time'': the time it takes for a catalyst to return back to its state before interacting. In the example above, the recovery time is 15.
* ''Recovery time'': the time it takes for a catalyst to return back to its state before interacting. In the example above, the recovery time is 15.
* ''Replacement catalyst'': When a common catalyst fails, another, less common, catalyst must be used.
* ''Replacement catalyst'': When a common catalyst fails, another, less common, catalyst must be used.
Line 103: Line 105:
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>


Both the eater head and eater tail can function as a snake catalyst:
Both the head and tail of a fishhook can function as a snake catalyst:
<center>{{LV:Viewer|
<center>{{LV:Viewer|
x = 25, y = 7, rule = LifeHistory
x = 26, y = 8, rule = LifeHistory
A.3A5.A.3A5.A.3A$.C9.C9.C2$2.2A8.2A8.2A$3.A9.A9.A$2.A10.A.A4.3A$2.2A
A9.A9.A$.A.3A5.A.3A5.A.3A$2.C9.C9.C2$3.2A8.2A8.2A$4.A9.A9.A$3.A10.A.A
10.2A4.A!
4.3A$3.2A10.2A4.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
 
It's important that the following red cell does not get born. Try replacing with a hook-with-tail if the red cell gets born.
<center>{{LV:Viewer|
x = 15, y = 7, rule = LifeHistory
2A.2A4.2A.2A$2.C.D6.C.D2$3.2A5.A.A$4.A5.2A.A$3.A9.A$3.2A8.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>


Line 143: Line 139:
* On generation 2, two more cells are born next to the tub. This causes the three white cells to die;
* On generation 2, two more cells are born next to the tub. This causes the three white cells to die;
* By generation 3, the cells in the center have died and what remains is a 5-cell parent of the tub. In all tub catalyses, the tub should turn into this 5-cell parent.
* By generation 3, the cells in the center have died and what remains is a 5-cell parent of the tub. In all tub catalyses, the tub should turn into this 5-cell parent.
===Ship===
Observe the following reaction:
<center>{{LV:Viewer|
x = 8, y = 9, rule = B3/S23
2bo$2o$b2o$3b3o3$5b2o$5bobo$6b2o!
[[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
The ship is turned into a relative of the [[I-heptomino]] (specifically a great-uncle) then is turned back into a ship by a perfectly-timed temporary induction. The ship rarely recovers by its own, but it's worth trying because it has replacement catalysts that recover much more often.


==Replacement catalyses==
==Replacement catalyses==
Line 171: Line 177:
[[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>


The most common replacement catalyst for a fishhook is the handy [[eater 2]]. An eater 2 recovers differently from an eater 1, making it more versatile. It can handle both of our problems:  
The most common replacement catalyst for a fishhook is the handy [[eater 2]]. An eater 2 recovers differently from an eater 1, making it more versatile (and its symmetry means that it can eat from two directions). It can handle both of our problems:  
<center>{{LV:Viewer|
<center>{{LV:Viewer|
x = 23, y = 11, rule = B3/S23
x = 23, y = 11, rule = B3/S23
Line 212: Line 218:
obo13bobo$3o14bobo13bobo12b3o13b3o13b3o13b3o$bo16bo15bo14bo15bo15bo15b
obo13bobo$3o14bobo13bobo12b3o13b3o13b3o13b3o$bo16bo15bo14bo15bo15bo15b
o$69b2o30b2o$b2o14b2o14b2o14b2o14b2o2b2o10b2o14b2o2b2o$b2o2b2o10b2o2b
o$69b2o30b2o$b2o14b2o14b2o14b2o14b2o2b2o10b2o14b2o2b2o$b2o2b2o10b2o2b
2o10b2o2b2o10b2o2b2o10b2o2b2o10b2o2b2o10b2o$5bobo13bobo13bobo13bobo13b
2o10b2o2b2o10b2o2b2o10b2o14b2o2b2o10b2o$5bobo13bobo13bobo13bobo29bobo
obo13bobo$7bo15bo15bo15bo15bo15bo$7b2o14b2o14b2o14b2o14b2o14b2o!
$7bo15bo15bo15bo31bo$7b2o14b2o14b2o14b2o30b2o!
[[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]}}</center>
[[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]}}</center>


Line 302: Line 308:


Note that this doesn't always work, since it requires a spark to recover properly.
Note that this doesn't always work, since it requires a spark to recover properly.
For the secondary boat-type catalysis, there will sometimes be a blinker next to the boat when it recovers that then destroys the boat.
<center>{{LV:Viewer|
x = 31, y = 6, rule = B3/S23
3bo11bo10bo$3bo11bobo9bo2bo$3bo2bo8bo11bobo$bo3b2o6bo11bo4bo$obo3bo5b
obo9bobo3bo$2o10b2o10b2o4bo!
[[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]}}</center>
When this happens, the boat can be replaced with a beehive with tail.
<center>{{LV:Viewer|
x = 34, y = 8, rule = B3/S23
6bo11bo10bo$6bo11bobo9bo2bo$6bo2bo8bo11bobo$3b2o3b2o5b2o10b2o4bo$2bo2b
o3bo4bo2bo8bo2bo3bo$bob2o8bob2o8bob2o4bo$bo11bo11bo$2o10b2o10b2o!
[[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]}}</center>
This also works if the part of the blinker that is farther away from the boat is modified.
<center>{{LV:Viewer|
x = 20, y = 10, rule = B3/S23
7bo11bo$5b2o10b2o$3bo11bo$3bo11bo$3bobo9bobo$bo10b2o$obo8bo2bo$2o8bob
2o$10bo$9b2o!
[[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]}}</center>


===Snake replacements===
===Snake replacements===


The only way to replace snake catalyses is by replacing them with a similar catalyst which does the same thing but might have better clearance. For example, if a snake is required to be in close proximity to a fishhook, the fishhook's interaction might destroy the snake (and subsequently the fishhook). In this case, replacing the snake with a higher-clearance second fishhook can prevent the interaction:  
Sometimes, the snake needs to be replaced them with a similar catalyst which does the same thing but might have better clearance. For example, if a snake is required to be in close proximity to a fishhook, the fishhook's interaction might destroy the snake (and subsequently the fishhook). In this case, replacing the snake with a higher-clearance second fishhook can prevent the interaction:  
<center>{{LV:Viewer|
<center>{{LV:Viewer|
x = 36, y = 9, rule = B3/S23
x = 36, y = 9, rule = B3/S23
Line 311: Line 338:
obobo8b2o$4bo26bo$b3o15bo8b3o$bo15bo10bo!
obobo8b2o$4bo26bo$b3o15bo8b3o$bo15bo10bo!
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
A problem that sometimes occurs with snake catalyses is that a certain cell above the snake (marked in red) will be born when the snake is supposed to be done interacting. When this happens, try replacing the snake with a hook with tail.
<center>{{LV:Viewer|
x = 18, y = 19, rule = LifeHistory
2A.2A8.3A$2.C.D9.C.D2$3.2A10.2A$4.A11.A$3.A11.A$3.2A10.2A6$2A.2A8.3A$
2.C.D9.C.D2$.A.A9.A.A$.2A.A8.2A.A$4.A11.A$4.2A10.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>


===Tub replacements===
===Tub replacements===
Line 337: Line 371:
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>


If the line is instead four or more cells long, a 15-cell catalyst works:
If the line is instead four or more cells long, a certain 15-cell catalyst works:
<center>{{LV:Viewer|
<center>{{LV:Viewer|
x = 18, y = 23, rule = LifeHistory
x = 18, y = 23, rule = LifeHistory
Line 344: Line 378:
A$4.A.A7.A.A$3.A.A7.A.A$.3A.A.A3.3A.A.A$A5.2A2.A5.2A$2A8.2A!
A$4.A.A7.A.A$3.A.A7.A.A$.3A.A.A3.3A.A.A$A5.2A2.A5.2A$2A8.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
===Ship replacements===
The ship family is fairly unique as a catalyst family. For most catalyst families, one places the namesake catalyst expecting it to work, and the replacement catalysts are reserves. On the other hand, a ship will almost always fail when attempting a ship-type catalyst, and it is the case that one of the replacement catalysts works much more often. However, I think that it is worth initially placing lone ships (as opposed to initially placing a replacement catalyst) for three reasons:
# It takes less time to draw a ship than to draw any of the replacement catalysts.
# It is easier to see which replacement catalyst, if any, will work by observing a lone ship than by observing any single replacement catalyst.
# A lone ship will occasionally work, and I don't want to miss when that happens. (If a lone ship works, none of the replacement catalysts will work.)
Often, the ship is turned into a loaf. Adding a fishhook turns it back into a ship:
<center>{{LV:Viewer|
x = 46, y = 30, rule = LifeHistory
14.A$16.2A$16.4A21.A$.A11.A4.A7.A15.A$2.A.A9.3A10.2A11.A.A$3.A12.A12.
A12.A2$4.2A11.2A11.2A11.2A$4.A.A10.A.A10.A.A10.A.A$4.D2A10.D2A10.D2A10.
D2A6$14.A$16.2A$16.4A21.A$.A11.A4.A7.A15.A$2.A.A9.3A10.2A11.A.A$3.A12.
A12.A12.A2$4.2A11.2A11.2A11.2A$4.A.A10.A.A10.A.A10.A.A$5.2A11.2A11.2A
11.2A2$2.2A11.2A11.2A11.2A$3.A12.A12.A12.A$3A10.3A10.3A10.3A$A12.A12.
A12.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
If the loaf parent has an extra cell in a certain position (so that it becomes a great-uncle of the I-heptomino), there's another replacement catalyst that works (which was discovered fairly recently to use in the [[R49]] conduit, so it is often called the "R49 catalyst"):
<center>{{LV:Viewer|
x = 14, y = 29, rule = LifeHistory
3.A$4.2A2$4.A.A$5.A2$5.D2A$6.A.A$6.D2A7$3.A$4.2A2$4.A.A$5.A2$6.2A$3.A
.A2.A$.3A.A.2A$A4.A$.3A.A4.2A$3.2A5.A$11.3A$13.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
It can work even if the chaos doesn't leave the ship/I-relative.
<center>{{LV:Viewer|
x = 74, y = 28, rule = LifeHistory
4.A59.A$4.A2.A18.A39.2A$4.A.A17.A.A17.A.A16.2A$5.A19.A19.A19.A2$5.D2A
17.D2A17.D2A17.D2A$6.A.A17.A.A17.A.A17.A.A$6.D2A17.D2A17.D2A17.D2A8$4.
A59.A$4.A2.A18.A39.2A$4.A.A17.A.A17.A.A16.2A$5.A19.A19.A19.A2$6.2A18.
2A18.2A18.2A$3.A.A2.A14.A.A2.A14.A.A2.A14.A.A2.A$.3A.A.2A12.3A.A.2A12.
3A.A.2A12.3A.A.2A$A4.A14.A4.A14.A4.A14.A4.A$.3A.A4.2A9.3A.A4.2A9.3A.A
4.2A9.3A.A4.2A$3.2A5.A12.2A5.A12.2A5.A12.2A5.A$11.3A17.3A17.3A17.3A$13.
A19.A19.A19.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
When considering replacing the ship with an R49 catalyst, it is very important that the marked cell has three live neighbors on generation two.
<center>{{LV:Viewer|
x = 5, y = 7, rule = LifeHistory
2.A$A.A$.A$3.D$2.2A$2.A.A$3.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
If the marked cell only has two live neighbors on generation two, don't bother placing an R49 catalyst; it won't work.
<center>{{LV:Viewer|
x = 54, y = 27, rule = LifeHistory
4.A42.A$4.A.A16.2A19.A.A$5.A19.A19.A$7.D19.D19.D$6.2A18.2A18.2A$6.A.A
17.A.A17.A.A$7.2A18.2A18.2A9$4.A42.A$4.A.A16.2A19.A.A$5.A19.A19.A2$6.
2A18.2A18.2A$3.A.A2.A14.A.A2.A14.A.A2.A$.3A.A.2A12.3A.A.2A12.3A.A.2A$
A4.A14.A4.A14.A4.A$.3A.A4.2A9.3A.A4.2A9.3A.A4.2A$3.2A5.A12.2A5.A12.2A
5.A$11.3A17.3A17.3A$13.A19.A19.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
A fishhook bridge fishhook works when the ship turns into a certain blockade predecessor.
<center>{{LV:Viewer|
x = 48, y = 31, rule = LifeHistory
.A38.A$.A20.A17.A2.A$2.A19.A16.A.A2.A$.A17.2A.A18.A2.A$.A19.A19.A2$.D
AC17.DAC17.DAC$.DC.C16.DC.C16.DC.C$2.D2C17.D2C17.D2C12$.A38.A$.A20.A17.
A2.A$2.A19.A16.A.A2.A$.A17.2A.A18.A2.A$.A19.A19.A2$2.2A18.2A18.2A$2.A
.A17.A.A17.A.A$A.A.3A13.A.A.3A13.A.A.3A$2A5.A12.2A5.A12.2A5.A$6.2A18.
2A18.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 T 4 PAUSE 1 ]]}}</center>
Lone ships, ship-fishhook pairs, and R49 catalysts are more likely to work when the cell that "activates" them survives into the next generation, while a fishhook bridge fishhook catalyst is more likely to work if by the next generation, the cell that "activated" it has died, and it has a two-cell edge to "slam" into. Common examples of the latter are a grin (like in [[30P6.1]]) and a certain edgeshootable beehive predecessor.
<center>{{LV:Viewer|
x = 18, y = 11, rule = LifeHistory
11.A$.A9.A$2.A9.A$2.A8.A$.C9.C2$2.2A8.2A$2.A.A7.A.A$A.A.3A3.A.A.3A$2A
5.A2.2A5.A$6.2A8.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
While this is a trend, this is not a hard-and-fast rule. Here are demonstrations of this from earlier in this section:
<center>{{LV:Viewer|
x = 51, y = 13, rule = LifeHistory
14.A14.A15.A$A14.A15.2A12.A$.2A10.A.A12.2A12.2A.A$3.C11.C14.C13.C2$4.
2A10.2A13.2A12.2A$4.A.A9.A.A9.A.A2.A11.A.A$5.2A10.2A7.3A.A.2A9.A.A.3A
$25.A4.A12.2A5.A$2.2A10.2A10.3A.A4.2A12.2A$3.A11.A12.2A5.A$3A9.3A21.
3A$A11.A25.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
For this reason, as well as the fact that a ship takes less time to draw than a fishhook bridge fishhook (and I can still tell whether or not a fishhook bridge fishhook will work by observing a ship), I place a long ship instead of a fishhook bridge fishhook even in situations that look like a fishhook bridge fishhook is the most likely ship-type catalyst to work.
Occassionally, instead of simply becoming the aforementioned blockade predecessor, the ship will become that blockade predecessor with three additional cells, and if one uses a fishhook bridge fishhook, it will mostly recover, but there will be three extra cells in the same position. When this happens (One only needs to observe this for one of those two catalysts.), a beehive works.
<center>{{LV:Viewer|
x = 69, y = 43, rule = LifeHistory
62.A$2A2.A13.A44.2A$.A2.A14.2A18.A.A.A15.A$2.A2.A15.2A15.2A.2A17.2A.A
$2.A2D17.A2D13.A3.A2D17.A2D$4.D19.D19.D19.D$2.DAC17.DAC17.DAC17.DAC$
2.DC.C16.DC.C16.DC.C16.DC.C$3.D2C17.D2C17.D2C17.D2C9$62.A$2A2.A13.A
44.2A$.A2.A14.2A18.A.A.A15.A$2.A2.A15.2A15.2A.2A17.2A.A$2.A2D17.A2D
13.A3.A2D17.A2D$4.D19.D19.D19.D$3.2A18.2A18.2A18.2A$3.A.A17.A.A17.A.A
17.A.A$.A.A.3A13.A.A.3A13.A.A.3A13.A.A.3A$.2A5.A12.2A5.A12.2A5.A12.2A
5.A$7.2A18.2A18.2A18.2A7$62.A$2A2.A13.A44.2A$.A2.A14.2A18.A.A.A15.A$
2.A2.A15.2A15.2A.2A17.2A.A$2.A19.A15.A3.A19.A2$3.2A18.2A18.2A18.2A$2.
A2.A16.A2.A16.A2.A16.A2.A$3.2A18.2A18.2A18.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 T 4 PAUSE 1 ]]}}</center>


==Bonus catalyses==
==Bonus catalyses==
Line 373: Line 503:
The eater 3 has some other applications besides eating gliders, for example the [[rectifier]].
The eater 3 has some other applications besides eating gliders, for example the [[rectifier]].


===Ship===
===Ship (again)===


The ship has a transparent catalysis not similar to other catalysts where it deletes half of a [[traffic light]]:  
The ship has a pseudo-transparent catalysis not similar to other catalysts where it deletes half of a [[traffic light]]:  
<center>{{LV:Viewer|
<center>{{LV:Viewer|
x = 7, y = 6, rule = B3/S23
x = 7, y = 6, rule = B3/S23
Line 381: Line 511:
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
This may seem pretty niche, but it is actually a fairly common application.
This may seem pretty niche, but it is actually a fairly common application.
===Loaf===
Besides its usage in the eater 3, the loaf has a pseudo-transparent catalysis that can eat a certain beehive predecessor or two block predecessors that are similar to each other.
<center>{{LV:Viewer|
x = 32, y = 7, rule = B3/S23
o2$b3o8bob2o10b2o$5bo7bo3bo6b2o3bo$4bobo9bobo9bobo$4bo2bo8bo2bo8bo2bo
$5b2o10b2o10b2o!
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
This type of loaf catalysis is used in Kazyan's method of restoring a block that has been turned into a beehive while generating a Herschel.
<center>{{LV:Viewer|
x = 15, y = 18, rule = B3/S23
obo$b2o$bo8$8b2o$7bo2bo$8b2o2$12bo$11bobo$11bo2bo$12b2o!
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>


===Hook with tail===
===Hook with tail===
Line 386: Line 530:
The hook with tail can serve as a rock:  
The hook with tail can serve as a rock:  
<center>{{LV:Viewer|
<center>{{LV:Viewer|
x = 30, y = 13, rule = B3/S23
x = 54, y = 13, rule = B3/S23
19b2o2$21bo$19bo2bo4b2o$19bo2bo4bobo$20b3o5bo$b2ob2o5b3o$3bo8bo2$2bob
43b2o2$26bo18bo$26bo16bo2bo4b2o$27bo2bo12bo2bo4bobo$27b3o14b3o5bo$b2o
o6bobo6bobo$bob2o5bob2o5bob2o$bo8bo8bo$2o7b2o7b2o!
b2o4b3o4b5o12bob3o$3bo7bo8bo14bo2$2bobo5bobo6bobo5bobo5bobo6bobo$bob2o
4bob2o5bob2o4bob2o4bob2o5bob2o$bo7bo8bo7bo7bo8bo$2o6b2o7b2o6b2o6b2o7b
2o!
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>


Line 397: Line 543:
!
!
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
[[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]}}</center>
===Ship (again)===
Observe the following reaction:
<center>{{LV:Viewer|
x = 8, y = 9, rule = B3/S23
2bo$2o$b2o$3b3o3$5b2o$5bobo$6b2o!
[[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
The ship rarely recovers by its own, but it's worth trying because it has replacement catalysts that recover much more often.
Often, the ship is turned into a loaf. Adding a fishhook turns it back into a ship:
<center>{{LV:Viewer|
x = 46, y = 30, rule = LifeHistory
14.A$16.2A$16.4A21.A$.A11.A4.A7.A15.A$2.A.A9.3A10.2A11.A.A$3.A12.A12.
A12.A2$4.2A11.2A11.2A11.2A$4.A.A10.A.A10.A.A10.A.A$4.D2A10.D2A10.D2A10.
D2A6$14.A$16.2A$16.4A21.A$.A11.A4.A7.A15.A$2.A.A9.3A10.2A11.A.A$3.A12.
A12.A12.A2$4.2A11.2A11.2A11.2A$4.A.A10.A.A10.A.A10.A.A$5.2A11.2A11.2A
11.2A2$2.2A11.2A11.2A11.2A$3.A12.A12.A12.A$3A10.3A10.3A10.3A$A12.A12.
A12.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
If the loaf parent has an extra cell in a certain position, there's another replacement catalyst that works (which was discovered fairly recently to use in the [[R49]] conduit, so it is often called the "R49 catalyst"):
<center>{{LV:Viewer|
x = 14, y = 29, rule = LifeHistory
3.A$4.2A2$4.A.A$5.A2$5.D2A$6.A.A$6.D2A7$3.A$4.2A2$4.A.A$5.A2$6.2A$3.A
.A2.A$.3A.A.2A$A4.A$.3A.A4.2A$3.2A5.A$11.3A$13.A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
===Eater bridge eater===
The eater bridge eater catalyst occurs when there is a one cell leading edge of an active region which "activates" the eater bridge (just like with the ship catalyses), with the next generation consisting of a two cell edge for the catalyst to "slam" into. For example:
<center>{{LV:Viewer|
x = 8, y = 9, rule = LifeHistory
.A.A$2.A$.C2$2.2A$2.A.A$A.A.3A$2A5.A$6.2A!
[[ GRID THUMBNAIL THUMBSIZE 2 ]]}}</center>
This catalyst also has some uses, like in [[30P6.1]].


===Eater 4===
===Eater 4===

Revision as of 19:47, 25 June 2021

A catalyst is a stable object (usually a still life) which can interact with an active region and later return to its original state. Catalysts are very useful in conduits and in many other applications. Here is an example of a stable catalyst:

x=11, y = 10, rule = LifeHistory 2.C$2.C$.2C6.2A$4.2A.A2.A$3.A.A.3A$A2.A.A$4A.3A$4.A3.A$2.A.A2.2A$2.2A ! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

The green still life interacts with the white object, and recovers to its original state by generation 15. In this tutorial, you'll learn the main types of catalyses and their applications. But first, we need to cover some important definitions:

Important terms

  • Stable catalyst: a catalyst which is a still life. Most catalyses are of this form. In this tutorial we will only focus on stable catalyses, as periodic catalyses are as of now quite underdeveloped.
  • Periodic catalyst: a catalyst which is an oscillator. These are generally considered inferior to stable catalyses because they usually only work in a fraction of the generations as a stable catalyst, since they usually only work in one phase of the periodic catalyst.
  • Transparent catalyst or transparent object: an object which is destroyed completely (all of its cells being off at the same time) then restored (in the same position and with the same orientation)
  • Pseudo-transparent catalyst: a catalyst that loses all of its cells but not at the same time (i.e. for each generation, at least one of its cells is alive)
  • Recovery time: the time it takes for a catalyst to return back to its state before interacting. In the example above, the recovery time is 15.
  • Replacement catalyst: When a common catalyst fails, another, less common, catalyst must be used.
  • Rock: A catalyst which does not lose any of its cells, even temporarily, during the interaction process. The snake-type catalyses below are examples of rocks.

Let's explore the different types of catalysts now!

Types of common catalyses

Fishhook (eater 1)

Here are some examples of fishhook catalyses:

x=28, y = 7, rule = LifeHistory 2.A8.2A7.A.A$A.C8.AC9.C$.AC8.AC7.2AC$4.2A8.2A8.2A$4.A.A7.A.A7.A.A$6.A 9.A9.A$6.2A8.2A8.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

The marked white cells should always be on in a fishhook-type catalyst. Sometimes, the fishhook may engage in a more unusual manner, but these are rarer:

x=22, y = 6, rule = B3/S23 2o3b2o8b2o$3ob2o8b2o$4bo3b2o4bo3b2o$8bobo7bobo$10bo9bo$10b2o8b2o! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

In the second example, the fishhook later catalyses a blinker. This catalysis is often useful.

Even rarer is when the tail of the eater is to be used as a rock (the red cells must not be born):

x=8, y = 7, rule = LifeHistory 6.2A$7.A$4.3A$3.DA$4.D$.3C$A3.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Recognizing when to use a fishhook catalysis is really a matter of experience. For practice, try placing an eater 1 somewhere within this blue field to eat the middleweight spaceship (click on the thumbnail below to draw cells in LifeViewer using the pencil icon):

x=18, y = 9, rule = LifeHistory .5A$A4.A$5.A4.8B$A3.A5.8B$2.A7.8B$10.8B$10.8B$10.8B$10.8B! [[ GRID THUMBNAIL THUMBSIZE 2 WIDTH 800 HEIGHT 600 ]]

Block

Here are some examples of block catalyses:

x=18, y = 8, rule = LifeHistory 16.A$.A14.A$A.A5.3A6.A$A.A5.3A3.A.A$.C7.C5.C2$.2A5.2A4.2A$.2A5.2A4.2A ! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Block catalyses typically occur when there is a one cell leading edge of a pattern, shown in white above.

They are usually much easier to recognize than fishhook-type catalyses, however they may sometimes fail:

x=12, y = 6, rule = B3/S23 10b2o$ob2o5b2o$bo7bo2$b2o6b2o$b2o6b2o! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

Moving the block over by one often fixes this problem:

x=12, y = 6, rule = B3/S23 10b2o$ob2o5b2o$bo7bo2$2o6b2o$2o6b2o! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

As practice, try to eat this bun with a block placed in the blue region:

x=12, y = 6, rule = LifeHistory 6B$6B$6B2.3A$6B2.A2.A$6B3.2A$6B! [[ GRID THUMBNAIL THUMBSIZE 2 WIDTH 800 HEIGHT 600 ]]

Boat

Boat catalyses are rarer, but are still useful. Here are two examples:

x=23, y = 10, rule = LifeHistory 17.A$17.2A$2.A13.2A$.A.A$A2.2A$.2CB16.2DB2$2.A18.A$.A.A16.A.A$.2A17.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

They typically occur when there is a two cell leading edge, which is marked. Boat catalyses fail very often, so see the "Replacement catalysts" section below for potential replacement catalysts. As a general rule, boats are most likely to succeed when a cell adjacent to the leading edge (shown in blue) will turn on in the following generation.

Boats can also catalyze objects with a line of three cells, but it's important here that the red cell does not turn on:

x=8, y = 6, rule = LifeHistory 3.A3.A$6.A$2.D3C$.A$A.A$2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Snake

Snake catalyses are examples of rocks, or catalysts which do not change even temporarily when interacting with an object. They must function this way due to the fact that the two cells in the center would die from overpopulation due to already having three live neighbors.

Three example snake catalysts are shown below. The white cells should always be on to trigger the important next generation, where the snake functions as a rock:

x=24, y = 9, rule = LifeHistory 15.A6.A$4.A8.2A8.A$2A.2A6.2A7.A.2A$.C9.C9.C2$2.2A8.2A8.2A$3.A9.A9.A$ 2.A9.A9.A$2.2A8.2A8.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Both the head and tail of a fishhook can function as a snake catalyst:

x=26, y = 8, rule = LifeHistory A9.A9.A$.A.3A5.A.3A5.A.3A$2.C9.C9.C2$3.2A8.2A8.2A$4.A9.A9.A$3.A10.A.A 4.3A$3.2A10.2A4.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Conduit 1 is an example of a conduit using a snake catalyst. Try to catalyze the reaction below with a snake in the blue field (as a hint, the cell which should trigger the rock interaction is marked):

x=15, y = 7, rule = LifeHistory 7B$7B4.2A.A$7B5.3A$7B6.A$7BD$7B4.2A$7B4.2A! [[ GRID THUMBNAIL THUMBSIZE 2 WIDTH 800 HEIGHT 600 ]]

Tub

Tub catalyses can be tricky to find, but they are most likely to work when the frontend of the active region is two or three cells long, like one of the examples below:

x=39, y = 73, rule = LifeHistory 25.A12.A$4.A5.A10.A3.A$3A5.A.A15.A7.A.2A$3A5.3A7.3A6.2A6.2A2$2.A7.A7. A7.A7.A$.A.A5.A.A5.A.A5.A.A5.A.A$2.A7.A7.A7.A7.A4$17.A2$17.A2$14.A2.A 2.A2$15.A.A.A2$17.A3$.A7.A15.2A10.A$A.2A4.A.2A7.2A5.2A8.2A$A.A5.A.A8. A7.A7.3A$2.C7.C7.C8.C7.C$2.A7.A7.A7.A7.A$.A.A5.A.A5.A.A5.A.A5.A.A$2.A 7.A7.A7.A7.A4$17.A2$17.A2$14.A2.A2.A2$15.A.A.A2$17.A3$.2A6.2A14.3A8. 2A$A.2A4.A.2A7.2A4.A.A7.A2.A$2.A7.A7.3A6.2A6.A.A$2.2C6.2C6.2C6.2C6.2C $.2AC5.2AC5.2AC6.AC6.AC$.A.A5.A.A5.A.A5.A.A5.A.A$2.A7.A7.A7.A7.A4$17. A2$17.A2$14.A2.A2.A2$15.A.A.A2$17.A4$26.A$.3A5.3A13.A.A8.2A$3.A7.A6.A .A4.A9.A2.A$28.A6.A2$.A2.A4.A2.A4.A2.A4.A2.A4.A2.A$.A.A5.A.A5.A.A5.A. A5.A.A$2.A7.A7.A7.A7.A! [[ GRID THUMBNAIL THUMBSIZE 2 WIDTH 500 HEIGHT 700 ]]

The reactions start differently but end up the same way through the same general mechanism:

  • On generation 1, one cell (marked in white) is born next to the tub;
  • On generation 2, two more cells are born next to the tub. This causes the three white cells to die;
  • By generation 3, the cells in the center have died and what remains is a 5-cell parent of the tub. In all tub catalyses, the tub should turn into this 5-cell parent.

Ship

Observe the following reaction:

x=8, y = 9, rule = B3/S23 2bo$2o$b2o$3b3o3$5b2o$5bobo$6b2o! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

The ship is turned into a relative of the I-heptomino (specifically a great-uncle) then is turned back into a ship by a perfectly-timed temporary induction. The ship rarely recovers by its own, but it's worth trying because it has replacement catalysts that recover much more often.

Replacement catalyses

So, you've tried to catalyze a reaction, but the common catalyst fails! Luckily for you, this is not a complete disaster, since many replacement catalysts exist exactly to assist you when your fishhook or block doesn't just work out.

Fishhook replacements

The most common way for a fishhook to fail is something like this:

x=8, y = 8, rule = B3/S23 o$o2bo$b3o2$4b2o$4bobo$6bo$6b2o! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

Luckily, this is also the easiest to fix. Simply flip the eater 1 around and it works!

x=32, y = 9, rule = B3/S23 o15bo$o2bo20bo$b3o14bo5bo2bo$25b3o$4b2o4bobobobobobo$4bobo21b2o$6bo11b o9bo$6b2o21b3o$16bo14bo! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

This was a bit cheating, however. Sometimes, we need a genuinely new catalyst. Here are two almost-catalyses where the fishhook almost recovers, but an extra spark destroys it or an extra cell gets attached to its recovering phase:

x=20, y = 8, rule = B3/S23 12bo$o10bobo$b2o10b2o$2o12bo$4b2o7bo2b2o$4bobo9bobo$6bo11bo$6b2o10b2o! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

The most common replacement catalyst for a fishhook is the handy eater 2. An eater 2 recovers differently from an eater 1, making it more versatile (and its symmetry means that it can eat from two directions). It can handle both of our problems:

x=23, y = 11, rule = B3/S23 12bo$o10bobo$b2o10b2o$2o12bo$4b2obo5bo2b2obo$4b2ob3o6b2ob3o$10bo11bo$ 4b2ob3o6b2ob3o$5bobo9bobo$5bobo9bobo$6bo11bo! [[ THEME 6 GRID THUMBNAIL THUMBSIZE 2 ]]

There are many, many more cases in which neither an eater 1 nor an eater 2 works. This guide, courtesy of Entity Valkyrie, addresses many of these:

x=975, y = 63, rule = EV2QuadColor 99.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F$27.3F.3F.3F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F$27.F3.F3.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F$27.F3.2F2.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F$27.F.F.F3.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F$27.3F.3F.F.F$103.3F69.3F69.3F69.3F69.3F69.3F69.F.F69.3F69.3F69.3F69.F.F69.F.F69.F.F$31.3F71.F71.F71.F69.F73.F71.F69.F.F71.F69.F73.F69.F.F69.F.F69.F.F$33.F69.3F69.3F71.F69.3F69.3F69.3F69.3F69.3F69.3F69.3F69.3F69.3F69.3F$31.3F69.F71.F73.F71.F71.F71.F71.F69.F73.F69.F73.F71.F71.F$31.F71.3F69.3F71.F69.3F69.3F69.3F71.F69.3F69.3F69.3F71.F71.F71.F$31.3F2$864.2D$D504.D.D26.A112.D73.D142.3D$.3D70.D70.D68.D5.D67.D146.D71.D25.A2.A41.D69.D70.D.D71.2D70.D.2D$3.D16.H54.D16.H51.D.D17.H48.2D2.4D15.H51.3D17.H71.H54.D16.H10.A40.D2.D16.H9.3A41.D17.H51.D19.H51.D.D17.H54.D16.H51.2D.2D15.H49.D21.H$3.D16.2H10.A42.D16.2H50.D.2D16.2H47.D2.D2.D16.2H50.4D16.2H53.D16.2H51.D.D16.2H8.2A42.2D16.2H9.A43.D16.2H51.D.D16.2H9.A42.2D16.2H53.D16.2H48.D4.D16.2H9.A38.D3.2D16.2H8.A$3.D12.7H50.3D12.7H6.A45.D12.7H50.3D12.7H48.2D2.D12.7H9.A37.2D3.D12.7H51.2D12.7H51.2D12.7H51.2D12.7H50.3D12.7H7.A42.D.D12.7H7.A42.D.D12.7H49.D2.D12.7H48.D3.D12.7H8.A$5.2E9.8H7.AFE43.2E9.8H5.A2.FE40.D2.2E9.8H6.A.FE43.2E9.8H8.2E39.2D2.2E9.8H8.2E38.3D2.2E9.8H8.FE43.2E9.8H8.2E43.2E9.8H8.2E39.2D2.2E9.8H8.FE43.2E9.8H6.A.FE43.2E9.8H6.A.FE43.2E9.8H8.FE38.3D2.2E9.8H8.2E38.3D2.2E9.8H8.2E$5.E.E8.7H8.AE.E42.E.E8.7H8.AE.E42.E.E8.7H8.AE.E42.E.E8.7H9.E.E42.E.E8.7H9.E.E42.E.E8.7H9.E.E42.E.E8.7H9.E.E42.E.E8.7H9.E.E42.E.E8.7H9.E.E42.E.E8.7H8.AE.E42.E.E8.7H8.AE.E42.E.E8.7H7.A.E.E42.E.E8.7H7.A.E.E42.E.E8.7H7.A.E.E$7.E12.2H12.E44.E12.2H12.E44.E12.2H12.E44.E12.2H10.A.E44.E12.2H12.E44.E12.2H12.E44.E12.2H12.E44.E12.2H12.E38.D5.E12.2H12.E44.E12.2H12.E44.E12.2H12.E44.E12.2H9.A2.E34.2D8.E12.2H12.E44.E12.2H12.E$7.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E34.D8.2E11.H13.2E43.2E11.H13.2E9$367.2E25.2E468.2D$D366.E.E24.E.E108.D.D139.D73.D142.3D$.3D70.D70.D68.D5.D67.D80.E26.E38.D71.D70.D69.D70.D.D71.2D4.2E25.2E37.D.2D$3.D16.J54.D16.J51.D.D17.J48.2D2.4D15.J51.3D17.J59.2E.2E7.J14.2E.2E35.D16.H10.A40.D2.D16.J53.D17.H51.D19.H51.D.D17.H54.D4.E11.J14.E36.2D.2D65.D21.H$3.D16.2J10.A42.D16.2J50.D.2D16.2J47.D2.D2.D16.2J50.4D16.2J53.D5.E.E8.2J14.E.E34.D.D16.2H8.2A42.2D3.E12.2J12.E40.D16.2H51.D.D16.2H52.2D16.2H53.D4.E.2E8.2J13.E.2E31.D4.D27.A38.D3.2D16.2H8.A$3.D12.7J50.3D3.2E7.7J6.A4.2E39.D12.7J50.3D12.7J48.2D2.D12.7J9.A37.2D3.D2.3E2.E4.7J10.F2E2.E35.2D12.7H51.2D2.E.E7.7J10.E.E38.2D3.2E7.7H9.A.2E37.3D3.2E7.7H11.2E37.D.D12.7H7.A42.D.D2.3E2.E4.7J10.EFE2.E33.D2.D4.2E25.2E34.D3.D12.7H8.A$5.2E9.8J7.AFE43.E2.E7.8J5.A2.F2.E38.D2.2E.E7.8J6.A.FE.E41.2E9.8J8.FE39.2D2.2E9.8J8.FE38.3D2.E3.2E5.8J8.F3.2E39.2E.E7.8H8.EF.E41.E2.E7.8J8.F.AE37.2D2.E2.E7.8H8.F2.E41.E2.E7.8H7.AF2.E41.2E.E7.8H6.A.FE.E41.E3.2E5.8J8.F3.2E34.3D2.2E2.E22.2E2.E35.3D2.2E.E7.8H8.2F.E$5.E2.E7.7J8.AF2.E41.3E8.7J8.4E42.2E.3E5.7J8.AFE.3E39.E.E.2E5.7J9.E.E.2E39.E.E.2E5.7J9.F.E.2E39.4E7.7J9.4E41.2E.3E5.7H9.EF.3E39.2E.E.2E4.7J9.2E.E.2E38.3E8.7H9.3E42.3E8.7H7.2AF2E42.2E.3E5.7H8.AFE.3E39.4E7.7J9.F3E41.E.2E23.F.2E41.2E.3E5.7H7.A.2EA3E$6.2E.E10.2J11.2E.E55.2J61.E8.2J16.E40.E.E10.2J9.2A.E.E42.E.E10.2J9.2A.E.E43.E11.2J9.A3.E47.E8.2H11.A4.E39.E.E2.E8.2J11.E.E2.E34.D18.2H70.2H9.A51.E8.2H16.E41.E11.2J13.E33.2D8.E22.A.A.E48.E8.2H9.A.A4.E$9.E10.J15.E40.2E.E.2E8.J11.2E.E.2E38.2E.3E9.J11.2E.3E40.2E2.E9.J11.AFE2.E40.2E2.E9.J12.2E2.E39.2E.E.E9.J11.2E.E.E39.2E.3E9.H11.2E.3E38.E.E.2E10.J10.E.E.2E40.2E.E.2E8.H11.2E.E.2E38.2E.E.2E8.H11.2E.E.2E38.2E.3E9.H11.2E.3E39.2E.E.E9.J11.2E.E.E32.D6.E.E24.F.E42.2E.3E9.H11.2E.3E$9.2E25.2E40.E.2E.E21.E.2E.E39.E.E24.E.E44.2E22.A2.2E43.2E25.2E41.E2.2E22.E2.2E40.E.E24.E.E40.2E25.2E45.E.2E.E21.E.2E.E39.E.2E.E21.E.2E.E39.E.E24.E.E42.E2.2E22.E2.2E39.2E25.2E44.E.E24.E.E$78.E26.E44.E.E24.E.E42.2E25.2E43.2E25.2E41.E.E24.E.E44.E.E24.E.E114.E26.E44.E26.E44.E.E24.E.E40.E.E24.E.E116.E.E24.E.E$77.2E25.2E45.E26.E44.E26.E44.E26.E41.2E25.2E46.E26.E114.2E25.2E43.2E25.2E45.E26.E41.2E25.2E118.E26.E$223.E.E24.E.E42.E.E24.E.E$224.2E25.2E43.2E25.2E5$D646.D73.D$.3D431.D142.D4.2E25.2E36.D70.D.D$3.D16.J359.J54.D5.E10.J15.E109.D5.E11.J14.E36.D19.J51.D.D17.J193.D21.J$3.D16.2J341.D16.2J51.D.D3.3E10.2J12.3E110.D4.E.2E8.2J13.E.2E34.D.D16.2J52.2D16.2J192.D3.2D16.2J8.A$3.D2.2E8.7J10.2E323.2D3.D12.7J51.2D2.E9.7J10.E112.2D2.3E2.E4.7J10.3E2.E34.3D3.2E7.7J11.2E37.D.D2.2E8.7J7.A2.2E180.D3.D12.7J8.A$5.E.E8.8J7.AF.E325.3D2.2E9.8J8.FE43.E.E8.8J8.E.E110.2D2.E3.2E5.8J8.F3.2E39.E2.E7.8J8.E2.E41.E.E8.8J6.A.F.E181.3D2.2E.E7.8J8.2F.E$5.E10.7J9.E332.E.E8.7J9.E.E42.E.E8.7J9.E.E114.4E7.7J9.4E41.3E8.7J9.3E42.2E9.7J8.A2E187.2E.3E5.7J9.2EA3E$3.E.E14.2J8.E.E334.E12.2J10.A.E39.E3.E13.2J7.E3.E111.D6.E11.2J13.E38.E17.2J7.E51.2E9.2J14.2E189.E8.2J11.A4.E$.3E.E.E12.J7.3E.E.E331.2E.2E.E7.J12.2E.2E.E34.4E14.J8.4E116.2E.E.E9.J11.2E.E.E36.4E14.J8.4E41.2E5.E.E8.J8.2E5.E.E180.4E.3E9.J9.4E.3E$E5.2E19.E5.2E327.2E2.E2.E.2E16.2E2.E2.E.2E182.E2.2E22.E2.2E39.E26.E42.E7.E18.E7.E180.E3.2E21.E3.2E$2E25.2E332.E.E3.2E19.E.E3.2E38.2E25.2E117.E.E24.E.E42.E26.E40.3E8.2E14.3E8.2E180.2E25.2E$361.E26.E45.2E25.2E117.2E25.2E43.2E25.2E39.E26.E194.2E.E23.2E.E$360.2E25.2E553.E.2E23.E.2E! [[ THUMBNAIL THUMBSIZE 2 WIDTH 1200 HEIGHT 400 ]]

Here is an addendum by MathAndCode:

x=399, y = 59, rule = EV2QuadColor 100.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F61.3F.3F.3F$28.3F.3F.3F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F61.F3.F3.F.F$28.F3.F3.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F61.F3.2F2.F.F$28.F3.2F2.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F61.F.F.F3.F.F$28.F.F.F3.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F61.3F.3F.F.F$28.3F.3F.F.F$104.F.F69.3F69.F.F69.3F69.3F$32.3F69.F.F71.F69.F.F69.F71.F$32.F71.3F69.3F69.3F69.3F69.3F$32.3F71.F71.F71.F71.F69.F.F$34.F71.F69.3F71.F69.3F69.3F$32.3F2$73.D$293.D.D63.D.D$3.D68.D.D144.D66.D$4.D16.H53.2D16.H54.D16.H54.D16.H49.3D3.D15.H51.3D17.H$4.D16.2H50.D.2D16.2H53.D16.2H8.D44.D16.2H53.D16.2H51.3D16.2H$4.D12.7H9.A41.2D12.7H51.2D12.7H7.D42.D.D12.7H51.2D12.7H10.A36.D4.D12.7H$D5.2E9.8H8.FE43.2E9.8H6.A.2E43.2E9.8H8.2E43.2E9.8H5.A2.FE43.2E9.8H8.2F38.2D3.2E9.8H8.2E$.3D2.E.E8.7H9.E.E42.E.E8.7H8.AE.E42.E.E8.7H9.E.E42.E.E8.7H7.A.E.E42.E.E8.7H8.AE.E37.D4.E.E8.7H9.E.E$8.E12.2H12.E44.E12.2H12.E44.E12.2H12.E44.E12.2H9.A2.E44.E12.2H12.E44.E12.2H12.E$8.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H13.2E43.2E11.H12.A2E9$73.D$293.D.D63.D.D$3.D68.D.D144.D66.D$4.D16.J53.2D16.J54.D16.J54.D16.J49.3D3.D15.J51.3D17.J$4.D16.2J50.D.2D16.2J53.D16.2J8.A44.D16.2J53.D16.2J51.3D16.2J$4.D12.7J51.2D3.2E7.7J11.2E38.2D12.7J7.A42.D.D12.7J51.2D3.2E7.7J11.2E34.D4.D12.7J$D5.2E9.8J8.2E43.E2.E7.8J6.A.E2.E41.2E.E7.8J8.EF.E41.2E9.8J8.FE43.E2.E7.8J8.F2.E36.2D3.2E9.8J8.2E$.3D2.E.E8.7J9.E.E42.3E8.7J9.3E42.2E.3E5.7J9.EF.3E39.E.E8.7J8.AE.E42.3E8.7J8.A3E37.D4.E.E8.7J9.E.E$7.2E12.2J11.2E57.2J9.A51.E8.2J11.A4.E35.E4.E12.2J7.E4.E39.E17.2J7.E49.E12.2J12.E$21.J56.2E.E.2E8.J11.2E.E.2E38.2E.3E9.J11.2E.3E36.5E13.J8.5E40.4E14.J8.4E46.E.2E9.J13.E.2E$79.E.2E.E21.E.2E.E39.E.E24.E.E113.E26.E45.2E.2E22.2E.2E$79.E26.E44.E.E24.E.E40.E26.E44.E26.E$78.2E25.2E45.E26.E40.E.E24.E.E43.2E25.2E$221.E26.E5$73.D2$72.D.D$75.2D16.J$73.D.2D3.2E11.2J12.2E$75.2D4.E7.7J9.A2.E$78.3E8.8J6.A.3F$78.E10.7J8.AE.A$93.2J$93.J! [[ THUMBNAIL THUMBSIZE 2 WIDTH 1200 HEIGHT 400 ]]

Block replacements

Sometimes, a block that fails only needs to be supported with another catalyst, not replaced entirely. Take this, for example:

x=9, y = 9, rule = LifeHistory 2.2A$2.2A2$5.3D2$7.2A$.3A3.2A$.A.A$.A.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

The catalyst almost works, but then an extra blinker, shown in red, destroys it. If only we could get rid of that blinker...

Oh, right! We can use what we just learned in this tutorial! Adding an extra fishhook suppresses the blinker and allows the catalyst to work:

x=12, y = 10, rule = B3/S23 11bo$2b2o5b3o$2b2o4bo$8b2o3$7b2o$b3o3b2o$bobo$bobo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

This trick works in a variety of circumstances where a block fails because unwanted cells are born to one side. Also, the fishhook can occasionally be replaced by a block. This sometimes works even if a fishhook doesn't work.

x=103, y = 30, rule = B3/S23 82bo$83bo$15bo19bo13b2o31b2o$15bo18bo14b3o26b3ob2o$o16bobo13bo14bob2o 28bobo$3o14bobo13bobo12b3o29b3o$bo16bo15bo14bo31bo2$b2o14b2o14b2o14b2o 30b2o$b2o14b2o14b2o14b2o30b2o8$82bo15bo$83bo15bo$15bo19bo13b2o14b2o15b 2o14b2o$15bo18bo14b3o13b3o10b3ob2o10b3ob2o$o16bobo13bo14bob2o12bob2o12b obo13bobo$3o14bobo13bobo12b3o13b3o13b3o13b3o$bo16bo15bo14bo15bo15bo15b o$69b2o30b2o$b2o14b2o14b2o14b2o14b2o2b2o10b2o14b2o2b2o$b2o2b2o10b2o2b 2o10b2o2b2o10b2o2b2o10b2o14b2o2b2o10b2o$5bobo13bobo13bobo13bobo29bobo $7bo15bo15bo15bo31bo$7b2o14b2o14b2o14b2o30b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

Another example where a block catalyst can be fixed by supporting the block with another catalyst comes from the following example, where the block is turned into a first cousin of the century then crashes into a boat.

x=5, y = 8, rule = B3/S23 b2o$b2o3$3o$obo$3bo$4bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

In this case, the block can be supported by another block. In fact, two positions work.

x=24, y = 8, rule = B3/S23 5b2o13b2o$2o3b2o13b2o$2o13b2o$15b2o$4b3o12b3o$4bobo12bobo$7bo14bo$8bo14bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

This trick only works if there is something for the century cousin to crash into (and even then, not always), but luckily, there is an actual replacement catalyst for when the block is turned into a century cousin with nothing to hit.

x=19, y = 10, rule = B3/S23 o11bo$b3o9b3o$2bo11bo2$2b2o10b2o2bo$2b2o9bob4o$11b3o$10bo3b3o$11b3o2bo$13bo!5b2o13b2o$2o3b2o13b2o$2o13b2o$15b2o$4b3o12b3o$4bobo12bobo$7bo14bo$8bo14bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

There is another replacement catalyst for when the block is turned into an L-tetromino (a common beehive predecessor).

x=22, y = 14, rule = B3/S23 3bo15bo$3bo15bo$3bo15bo$3bo15bo$3o13b3o$bo15bo2$b2o14b2o$b2o12bo2bo$15b 2obobo$18b2obo$15b3o3bo$15bo2b3o$18bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

It should be noted that when a block fails in one of the most recent two ways, it can often be replaced with a hook with tail (although the hook with tail is not a replacement catalyst for the block in the strictest sense).

x=17, y = 25, rule = B3/S23 15bo$15bo$15bo$o14bo$b3o8b3o$2bo10bo2$2b2o9b2o$2b2o9b2o6$15bo$15bo$15b o$o14bo$b3o8b3o$2bo10bo2$bobo8bobo$b2obo7b2obo$4bo10bo$4b2o9b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

If a block is turned into a P-pentomino in a certain way, it can be replaced with a boat—or a fishhook bridge fishhook.

x=32, y = 9, rule = B3/S23 bo10bo10bo$4obo5b4obo5b4obo$4bo10bo10bo2$4b2o9b2o9b2o$4b2o9bobo8bobo$ 16bo7bobob3o$24b2o5bo$30b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

There is another replacement catalyst for another way in which the block is sometimes turned into a P-pentomino.

x=20, y = 13, rule = B3/S23 obo11bobo$b2o12b2o$3bobo11bobo$3bobo11bobo$4bo13bo2$3b2o12b2o$3b2o12b 2o$14bo$14b5o$18bo$16bo$16b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

In addition, there is a third way in which a block is sometimes turned into a P-pentomino. In this case, it can be replaced with a claw with tail supported by a fishhook.

x=21, y = 10, rule = B3/S23 3bo13bo$3bo13bo$obo11bobo$bo13bo2$b2o12b2o$b2o8b2o2bo2bo$10bobo3b2obo $10bo8bo$9b2o8b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

This also works if it's turned into an L-tetromino.

x=21, y = 10, rule = B3/S23 2bo13bo$3bo13bo$obo11bobo$bo13bo2$b2o12b2o$b2o8b2o2bo2bo$10bobo3b2obo $10bo8bo$9b2o8b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

Boat replacements

Here is an example of a boat in need:

x=3, y = 8, rule = LifeHistory .A$2.A$3A2$D$.A$A.A$.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

In this example, the white cell at generation 4 gets turned on when it shouldn't. We have a fix for this, as usual. Replace the boat with a tub with tail and block (this catalyst is called an eater 5 or tub-with-tail eater:

x=9, y = 10, rule = B3/S23 5bo$6bo$4b3o2$2o$2o3bo$4bobo$5bobo$7bo$7b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

Boats can also fail much more spectacularly:

x=8, y = 4, rule = B3/S23 6bo$3o2bobo$obo3b2o$obo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

In this case, the boat can be replaced by this (often called the "gourmet catalyst" due to its use in gourmet):

x=10, y = 10, rule = B3/S23 8b2o$7bobo$7bo$6b2o2$6b2o$3o2bobo$obo3bo$obo4b3o$9bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

Note that this doesn't always work, since it requires a spark to recover properly.

For the secondary boat-type catalysis, there will sometimes be a blinker next to the boat when it recovers that then destroys the boat.

x=31, y = 6, rule = B3/S23 3bo11bo10bo$3bo11bobo9bo2bo$3bo2bo8bo11bobo$bo3b2o6bo11bo4bo$obo3bo5b obo9bobo3bo$2o10b2o10b2o4bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

When this happens, the boat can be replaced with a beehive with tail.

x=34, y = 8, rule = B3/S23 6bo11bo10bo$6bo11bobo9bo2bo$6bo2bo8bo11bobo$3b2o3b2o5b2o10b2o4bo$2bo2b o3bo4bo2bo8bo2bo3bo$bob2o8bob2o8bob2o4bo$bo11bo11bo$2o10b2o10b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

This also works if the part of the blinker that is farther away from the boat is modified.

x=20, y = 10, rule = B3/S23 7bo11bo$5b2o10b2o$3bo11bo$3bo11bo$3bobo9bobo$bo10b2o$obo8bo2bo$2o8bob 2o$10bo$9b2o! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

Snake replacements

Sometimes, the snake needs to be replaced them with a similar catalyst which does the same thing but might have better clearance. For example, if a snake is required to be in close proximity to a fishhook, the fishhook's interaction might destroy the snake (and subsequently the fishhook). In this case, replacing the snake with a higher-clearance second fishhook can prevent the interaction:

x=36, y = 9, rule = B3/S23 7bo26bo$2o4bo20b2o4bo$bo4b3o8bo10bo4b3o$o18bo5b3o$2o23bo$3b2o6bobobob obobo8b2o$4bo26bo$b3o15bo8b3o$bo15bo10bo! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

A problem that sometimes occurs with snake catalyses is that a certain cell above the snake (marked in red) will be born when the snake is supposed to be done interacting. When this happens, try replacing the snake with a hook with tail.

x=18, y = 19, rule = LifeHistory 2A.2A8.3A$2.C.D9.C.D2$3.2A10.2A$4.A11.A$3.A11.A$3.2A10.2A6$2A.2A8.3A$ 2.C.D9.C.D2$.A.A9.A.A$.2A.A8.2A.A$4.A11.A$4.2A10.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Tub replacements

Sometimes, a single dot at the end of the tub parent is replaced with a line of three cells, causing the tub to turn into a block instead of recovering:

x=24, y = 12, rule = LifeHistory 22.2A$21.2A$20.2A$A5.A2$.2A.2A$3.A$6.D15.D$6.D15.D$4.A15.A$3.A.A13.A. A$4.A15.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

When this occurs, the tub should be replaced with this catalyst:

x=30, y = 18, rule = B3/S23 23b2o$22b2o$21b2o$bo5bo2$2b2ob2o$4bo3$5bo15bo$4bobo13bobo$3bobo13bobo$ b3o2b3o3b2o3b3o2b3o3b2o$o3b2o3bo2b2o2bo3b2o3bo2b2o$b3o2b2obo7b3o2b2obo $3bobo2bo10bobo2bo$4bobo13bobo$5bo15bo! [[ GRID THUMBNAIL THEME 6 THUMBSIZE 2 ]]

If this line of three cells is connected to something at the other end, a boat supported by a fishhook works:

x=21, y = 20, rule = LifeHistory 3.A$3.A10.A$3AD9.2D$3A.D8.2AC$4.D10.D$2.A10.A$.A.A8.A.A$2.A10.A3$3.A$ 3.A10.A$3AD9.2D$3A.D8.2AC$4.D10.D$2.A10.A$.A.A2.2A4.A.A2.2A$.2A3.A.A3. 2A3.A.A$8.A10.A$8.2A9.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

If the line is instead four or more cells long, a certain 15-cell catalyst works:

x=18, y = 23, rule = LifeHistory 16.A$6.A9.AD$2.A3.A9.AD$3.A.A.D9.D$4.A2.D7.2AC$7.D9.D$5.A9.A$4.A.A7.A .A$5.A9.A3$16.A$6.A9.AD$2.A3.A9.AD$3.A.A.D9.D$4.A2.D7.2AC$7.D9.D$5.A9. A$4.A.A7.A.A$3.A.A7.A.A$.3A.A.A3.3A.A.A$A5.2A2.A5.2A$2A8.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

Ship replacements

The ship family is fairly unique as a catalyst family. For most catalyst families, one places the namesake catalyst expecting it to work, and the replacement catalysts are reserves. On the other hand, a ship will almost always fail when attempting a ship-type catalyst, and it is the case that one of the replacement catalysts works much more often. However, I think that it is worth initially placing lone ships (as opposed to initially placing a replacement catalyst) for three reasons:

  1. It takes less time to draw a ship than to draw any of the replacement catalysts.
  2. It is easier to see which replacement catalyst, if any, will work by observing a lone ship than by observing any single replacement catalyst.
  3. A lone ship will occasionally work, and I don't want to miss when that happens. (If a lone ship works, none of the replacement catalysts will work.)

Often, the ship is turned into a loaf. Adding a fishhook turns it back into a ship:

x=46, y = 30, rule = LifeHistory 14.A$16.2A$16.4A21.A$.A11.A4.A7.A15.A$2.A.A9.3A10.2A11.A.A$3.A12.A12. A12.A2$4.2A11.2A11.2A11.2A$4.A.A10.A.A10.A.A10.A.A$4.D2A10.D2A10.D2A10. D2A6$14.A$16.2A$16.4A21.A$.A11.A4.A7.A15.A$2.A.A9.3A10.2A11.A.A$3.A12. A12.A12.A2$4.2A11.2A11.2A11.2A$4.A.A10.A.A10.A.A10.A.A$5.2A11.2A11.2A 11.2A2$2.2A11.2A11.2A11.2A$3.A12.A12.A12.A$3A10.3A10.3A10.3A$A12.A12. A12.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

If the loaf parent has an extra cell in a certain position (so that it becomes a great-uncle of the I-heptomino), there's another replacement catalyst that works (which was discovered fairly recently to use in the R49 conduit, so it is often called the "R49 catalyst"):

x=14, y = 29, rule = LifeHistory 3.A$4.2A2$4.A.A$5.A2$5.D2A$6.A.A$6.D2A7$3.A$4.2A2$4.A.A$5.A2$6.2A$3.A .A2.A$.3A.A.2A$A4.A$.3A.A4.2A$3.2A5.A$11.3A$13.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

It can work even if the chaos doesn't leave the ship/I-relative.

x=74, y = 28, rule = LifeHistory 4.A59.A$4.A2.A18.A39.2A$4.A.A17.A.A17.A.A16.2A$5.A19.A19.A19.A2$5.D2A 17.D2A17.D2A17.D2A$6.A.A17.A.A17.A.A17.A.A$6.D2A17.D2A17.D2A17.D2A8$4. A59.A$4.A2.A18.A39.2A$4.A.A17.A.A17.A.A16.2A$5.A19.A19.A19.A2$6.2A18. 2A18.2A18.2A$3.A.A2.A14.A.A2.A14.A.A2.A14.A.A2.A$.3A.A.2A12.3A.A.2A12. 3A.A.2A12.3A.A.2A$A4.A14.A4.A14.A4.A14.A4.A$.3A.A4.2A9.3A.A4.2A9.3A.A 4.2A9.3A.A4.2A$3.2A5.A12.2A5.A12.2A5.A12.2A5.A$11.3A17.3A17.3A17.3A$13. A19.A19.A19.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

When considering replacing the ship with an R49 catalyst, it is very important that the marked cell has three live neighbors on generation two.

x=5, y = 7, rule = LifeHistory 2.A$A.A$.A$3.D$2.2A$2.A.A$3.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

If the marked cell only has two live neighbors on generation two, don't bother placing an R49 catalyst; it won't work.

x=54, y = 27, rule = LifeHistory 4.A42.A$4.A.A16.2A19.A.A$5.A19.A19.A$7.D19.D19.D$6.2A18.2A18.2A$6.A.A 17.A.A17.A.A$7.2A18.2A18.2A9$4.A42.A$4.A.A16.2A19.A.A$5.A19.A19.A2$6. 2A18.2A18.2A$3.A.A2.A14.A.A2.A14.A.A2.A$.3A.A.2A12.3A.A.2A12.3A.A.2A$ A4.A14.A4.A14.A4.A$.3A.A4.2A9.3A.A4.2A9.3A.A4.2A$3.2A5.A12.2A5.A12.2A 5.A$11.3A17.3A17.3A$13.A19.A19.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

A fishhook bridge fishhook works when the ship turns into a certain blockade predecessor.

x=48, y = 31, rule = LifeHistory .A38.A$.A20.A17.A2.A$2.A19.A16.A.A2.A$.A17.2A.A18.A2.A$.A19.A19.A2$.D AC17.DAC17.DAC$.DC.C16.DC.C16.DC.C$2.D2C17.D2C17.D2C12$.A38.A$.A20.A17. A2.A$2.A19.A16.A.A2.A$.A17.2A.A18.A2.A$.A19.A19.A2$2.2A18.2A18.2A$2.A .A17.A.A17.A.A$A.A.3A13.A.A.3A13.A.A.3A$2A5.A12.2A5.A12.2A5.A$6.2A18. 2A18.2A! [[ GRID THUMBNAIL THUMBSIZE 2 T 4 PAUSE 1 ]]

Lone ships, ship-fishhook pairs, and R49 catalysts are more likely to work when the cell that "activates" them survives into the next generation, while a fishhook bridge fishhook catalyst is more likely to work if by the next generation, the cell that "activated" it has died, and it has a two-cell edge to "slam" into. Common examples of the latter are a grin (like in 30P6.1) and a certain edgeshootable beehive predecessor.

x=18, y = 11, rule = LifeHistory 11.A$.A9.A$2.A9.A$2.A8.A$.C9.C2$2.2A8.2A$2.A.A7.A.A$A.A.3A3.A.A.3A$2A 5.A2.2A5.A$6.2A8.2A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

While this is a trend, this is not a hard-and-fast rule. Here are demonstrations of this from earlier in this section:

x=51, y = 13, rule = LifeHistory 14.A14.A15.A$A14.A15.2A12.A$.2A10.A.A12.2A12.2A.A$3.C11.C14.C13.C2$4. 2A10.2A13.2A12.2A$4.A.A9.A.A9.A.A2.A11.A.A$5.2A10.2A7.3A.A.2A9.A.A.3A $25.A4.A12.2A5.A$2.2A10.2A10.3A.A4.2A12.2A$3.A11.A12.2A5.A$3A9.3A21. 3A$A11.A25.A! [[ GRID THUMBNAIL THUMBSIZE 2 ]]

For this reason, as well as the fact that a ship takes less time to draw than a fishhook bridge fishhook (and I can still tell whether or not a fishhook bridge fishhook will work by observing a ship), I place a long ship instead of a fishhook bridge fishhook even in situations that look like a fishhook bridge fishhook is the most likely ship-type catalyst to work.

Occassionally, instead of simply becoming the aforementioned blockade predecessor, the ship will become that blockade predecessor with three additional cells, and if one uses a fishhook bridge fishhook, it will mostly recover, but there will be three extra cells in the same position. When this happens (One only needs to observe this for one of those two catalysts.), a beehive works.

x=69, y = 43, rule = LifeHistory 62.A$2A2.A13.A44.2A$.A2.A14.2A18.A.A.A15.A$2.A2.A15.2A15.2A.2A17.2A.A $2.A2D17.A2D13.A3.A2D17.A2D$4.D19.D19.D19.D$2.DAC17.DAC17.DAC17.DAC$ 2.DC.C16.DC.C16.DC.C16.DC.C$3.D2C17.D2C17.D2C17.D2C9$62.A$2A2.A13.A 44.2A$.A2.A14.2A18.A.A.A15.A$2.A2.A15.2A15.2A.2A17.2A.A$2.A2D17.A2D 13.A3.A2D17.A2D$4.D19.D19.D19.D$3.2A18.2A18.2A18.2A$3.A.A17.A.A17.A.A 17.A.A$.A.A.3A13.A.A.3A13.A.A.3A13.A.A.3A$.2A5.A12.2A5.A12.2A5.A12.2A 5.A$7.2A18.2A18.2A18.2A7$62.A$2A2.A13.A44.2A$.A2.A14.2A18.A.A.A15.A$ 2.A2.A15.2A15.2A.2A17.2A.A$2.A19.A15.A3.A19.A2$3.2A18.2A18.2A18.2A$2. A2.A16.A2.A16.A2.A16.A2.A$3.2A18.2A18.2A18.2A! [[ GRID THUMBNAIL THUMBSIZE 2 T 4 PAUSE 1 ]]

Bonus catalyses

Here are some extra catalyses which might come in useful. This section is optional as the catalysts used are fairly rare.

Eater 3

You might notice that when you hit a loaf with a glider in a certain way, the loaf flips around:

x=15, y = 14, rule = B3/S23 2bo$obo$b2o$5b2o$4bo2bo$4bobo$5bo5$12b3o$12bo$13bo! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

This is quite inconvenient for us because we can't use the loaf again (unless we flip it back around with another glider as shown in the viewer, which is unlikely), but a stable catalyst does exist to turn the loaf back around. Here is the eater 3:

x=16, y = 15, rule = b3s23 2bo$obo$b2o$5b2o$4bo2bo2b2o$4bobo4bo2bo$5bo5bobobo$8b2obo2bo$8bo2bo$5b o4bo$5b5o2$7bo$6bobo$7bo! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

There is also a drifty variant of the eater 3 that catalyzes in the same way, but recovers differently:

x=11, y = 10, rule = b3s23 o$b2o$2o7b2o$4b2obo2bo$3bobob3o$3bobo$b3ob5o$o3bo4bo$2o2bobo$5b2o! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

The eater 3 has some other applications besides eating gliders, for example the rectifier.

Ship (again)

The ship has a pseudo-transparent catalysis not similar to other catalysts where it deletes half of a traffic light:

x=7, y = 6, rule = B3/S23 b2o$obo$2o2$5bo$4b3o! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

This may seem pretty niche, but it is actually a fairly common application.

Loaf

Besides its usage in the eater 3, the loaf has a pseudo-transparent catalysis that can eat a certain beehive predecessor or two block predecessors that are similar to each other.

x=32, y = 7, rule = B3/S23 o2$b3o8bob2o10b2o$5bo7bo3bo6b2o3bo$4bobo9bobo9bobo$4bo2bo8bo2bo8bo2bo $5b2o10b2o10b2o! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

This type of loaf catalysis is used in Kazyan's method of restoring a block that has been turned into a beehive while generating a Herschel.

x=15, y = 18, rule = B3/S23 obo$b2o$bo8$8b2o$7bo2bo$8b2o2$12bo$11bobo$11bo2bo$12b2o! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

Hook with tail

The hook with tail can serve as a rock:

x=54, y = 13, rule = B3/S23 43b2o2$26bo18bo$26bo16bo2bo4b2o$27bo2bo12bo2bo4bobo$27b3o14b3o5bo$b2o b2o4b3o4b5o12bob3o$3bo7bo8bo14bo2$2bobo5bobo6bobo5bobo5bobo6bobo$bob2o 4bob2o5bob2o4bob2o4bob2o5bob2o$bo7bo8bo7bo7bo8bo$2o6b2o7b2o6b2o6b2o7b 2o! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

One of its most common uses is to compactify the eater 5, called the 7x9 eater, which is used in a variety of conduits including the syringe:

x=14, y = 7, rule = B3/S23 3b2ob2o3b2o$2bobobobo2bobo$2bobo2bo3bo$b2obo$o3b2o$bobo2bobo$2ob2o2b2o ! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

Eater 4

The eater 4 primarily catalyses symmetrical objects. Its most common use is to catalyze a honey farm:

x=14, y = 15, rule = B3/S23 b2o$o2bo5b2o$3o7bo$10bob2o$9b2o2bo$6bo4b2o$6b5o$4b2o4bo$5bo2b2o$5bobo$ o2bobobo$4ob2o$4bo$2bobo$2b2o! [[ GRID THEME 6 THUMBNAIL THUMBSIZE 2 ]]

This can also come in handy sometimes; for example the recently-discovered L122 conduit.

Finding new catalysts

Mike Playle's Bellman is a search program specifically designed to search for new catalysts, given a reaction to be perturbed. It discovered the Snark, as well as many other highly notable patterns. This part of the tutorial hasn't been written yet, so consult the discussion thread and original documentation.

Another catalyst finding program is CatForce, which is a brute force placement program of certain given catalysts in a given area, and can also find transparent catalysts if they're restored quickly enough. It has also discovered quite a few interesting things, like B60.


Tutorials
Starting out
Software
Search methods
Python
Other Cellular Automata
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