LifeWiki - User contributions [en]

OCA:Live Free or Die

2026-07-27T16:42:53Z

SecondTypist: /* Spaceships */ linked free ship

{{Rule
|name = Live Free or Die
|imgname = lfodsample
|char = Explosive
|b = 2
|s = 0
|ruleinteger = 516
|reversal = B01234567/S01234578
|animated = true
}}
'''Live Free or Die''' (or '''LFoD''') is a [[Life-like cellular automaton]] where a cell survives if it has no neighbors, and a cell is born if it has two neighbors. Like {{rl|Seeds}}, LFoD naturally explodes at [[light speed]], but [[spaceship]]s, [[puffer]]s, and [[oscillator]]s of infinitely extensible size and [[period]] have been discovered, along with [[gun]]s, [[rake]]s, and spaceships which move diagonally.

==Notable patterns==

===Oscillators===
The rule also allows for the presence of only one [[still life]] consisting of a single cell, the dot. Other small oscillators include the checker ([[duoplet]]) at p2, the lever, anchor, and radar at p4, the ant at p6, and the monster at p19. The anchor track is an infinitely extensible oscillator that can have any period {{nowrap|{{times|4|2n}} - 4}}, which is useful in various flotillas of arbitrarily large periods. Oscillators have also been discovered at p3, p5, and p8. Many oscillators are extensible.

===Spaceships===

{{EmbedViewer
|pname = lfodmoon
|viewerconfig = [[ THUMBSIZE 3 ZOOM 42 GPS 1 X 0.5 AUTOSTART TRACKLOOP 1 -1 0 ]]
|position = center
|caption = The [[moon]] in Live Free or Die
|style = width:100px;
|apgcode = xq1_69/b2s0
}}

Most spaceships and puffers in Live Free or Die travel at light speed. There is one p1 spaceship with four cells, the moon. Other small, common [[photon]]s include the [[OCA:Live Free or Die/Free ship|free ship]] (p6), the key ship, plus ship, robot ship, and sun ship (p4), and the octopus ship (p8). Photons have also been discovered at p2, p3 and p5, and spaceship flotillas can be built with any period of the form {{nowrap|{{times|8|2n}}}} or {{nowrap|{{times|6|2n}}}}.

Spaceships that travel at c/2, 2c/5, c/3, c/4, and c/5 orthogonally and at c/4 diagonally have also been discovered.

===Puffers, rakes, and guns===
There are a large number of light speed puffers, including many small, common puffers that produce dots or checkers at p4. Other c puffers have been discovered at periods 3, 5, 6, 7, 8, and 9. Puffer flotillas can be built with any period of the form {{nowrap|{{times|8|2n}}}} or {{nowrap|{{times|6|2n}}}}, and complex flotillas can be built to produce oscillators like the monster and radar or to create rakes.

There are known c clean backward moon rakes at a variety of periods and at c/2 and c/5. Sideways or backward free ship rakes can be built using flotillas.

There is one known gun, a p4 double-barreled moon gun known as the moon laser discovered by [[Matthias Merzenich]] in August {{year|2012}}.<ref name="post6893" />

A non-chaotic [[breeder]] based on a p4 puffer was discovered by [[Arie Paap]] on March 5, {{year|2015}}.<ref name="post17412" />

===W110 unit cell===
On October 20, {{year|2020}}, [[FWKnightship]] constructed a [[Rule 110]] [[unit cell]] in Live Free or Die, proving the rule [[Turing-complete]].<ref name="post107139" />

==References==
<references>
<ref name="post6893">{{LinkForumThread
|format = ref
|title = Re: Live Free or Die
|p = 6893
|author = Matthias Merzenich
|date = August 1, 2012
}}</ref>
<ref name="post17412">{{LinkForumThread
|format = ref
|title = Re: Live Free or Die
|p = 17412
|author = Arie Paap
|date = March 5, 2015
}}</ref>
<ref name="post107139">{{LinkForumThread
|format = ref
|title = Re: List of the Turing-complete totalistic life-like CA
|p = 107139
|author = FWKnightship
|date = October 20, 2020
}}</ref>
</references>

==External links==
* {{LinkForumThread|f=11|t=649|title=Live Free or Die}}

* [https://web.archive.org/web/20150422141845/http://fano.ics.uci.edu/ca/rules/b2s0/g4.html Glider 7171] at [[David Eppstein]]'s [[glider.db|Glider Database]]
* {{LinkCatagolueRule|b2s0}}

[[Category:Life-like cellular automata]]
__NOTOC__

OCA:Live Free or Die/Free ship

2026-07-27T16:38:43Z

SecondTypist: Added info on discovery

{{stub}}
{{Spaceship
|name = Free ship
|pname = freeship
|c = 4
|bx = 10
|by = 5
|dir = Orthogonal
|p = 6
|m = 6
|s = 6c/6
|z = c
|h = 32
|symmetry = -e
|discoverer = Luke Bradford
|discoveryear =
|rulemin = B2/S0
|rulemax = B2567/S08
|isorulemin = B2-n/S0
|isorulemax = B23c4-acn567/S08
|rle = true
|viewerconfig = #C [[ WIDTH 750 HEIGHT 500 TRACKLOOP 6 1 0 X -0.5 THUMBSIZE 3 ZOOM 32 GPS 2 ]]
|apgcode = xq6_1owo1z128821/b2s0
}}
'''Free ship''' is a common period-6 [[photon]] in {{rl|Live Free or Die}} which has a large [[tail spark]], and can be turned into [[puffer]]s. Two of them emerge from the [[domino]] sequence. There is a shorter variant of the free ship called the '''short free ship''', but it is rarer due to not evolving from the domino.
{{EmbedViewer
|rle = x = 8, y = 6, rule = B2/S0
o4bo$3b2obo$7bo$7bo$3b2obo$o4bo!
|viewerconfig = #C [[ THUMBSIZE 2 WIDTH 750 AUTOSTART GPS 2 TRACKLOOP 6 1 0 ]]
|position = center
|caption = Short free ship
|style = width:300px;
|apgcode = xq6_4q11q4z4y04/b2s0
}}
The free ship was initially discovered by Luke Bradford, the creator of Live Free or Die, and was one of the patterns that initially interested him in the rule.<ref>{{cite web|url=http://mysite.verizon.net/live_free/|title=Live Free or Die Universe|last=Bradford|first=Luke|archiveurl=https://web.archive.org/web/20071101052121/http://mysite.verizon.net/live_free/|archivedate=November 1, 2007}}</ref>

== Gallery ==
{{EmbedViewer
|rle = x = 11, y = 17, rule = B2/S0
2bo4bo$5b2obo$10bo$10bo$5b2obo$2bo4bo6$o4bo$3b2obo$8bo$8bo$3b2obo$o4b
o!
|viewerconfig = #C [[ THUMBSIZE 2 WIDTH 750 HEIGHT 400 ]]
|position = center
|caption = A [[dot]] puffer consisting of two free ships
|style = width:300px;
}}

[[Category:Alien patterns]]
[[Category:Alien spaceships]]

Help:Formatting

2026-07-27T15:36:47Z

SecondTypist: Added {{About}} template at top of article that points to style guide

{{About|markup used on LifeWiki|when to use it|LifeWiki:Style guide}}
This page outlines the basic '''formatting''' commands that you will have to use in order to make your wiki articles easy to read. For example, this document will teach you how to make text '''bold''' or ''italic''. For a quicker introduction, see the [[Help:Quick_editing _guide|quick editing guide]]. For more thorough treatment of specific topics, see [[Help:Categories]], [[Help:Images]], [[Help:Links]], [[Help:Tables]], or [[Help:Templates]].

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{{ContributeNavbox}}

OCA:Live Free or Die/Free ship

2026-07-26T01:00:43Z

SecondTypist: SecondTypist moved page OCA:Life Free or Die/Free ship to OCA:Live Free or Die/Free ship: Misspelled title

{{stub}}
{{Spaceship
|name = Free ship
|pname = freeship
|c = 4
|bx = 10
|by = 5
|dir = Orthogonal
|p = 6
|m = 6
|s = 6c/6
|z = c
|h = 32
|symmetry =
|discoverer =
|discoveryear =
|rulemin = B2/S0
|rulemax = B2567/S08
|isorulemin = B2-n/S0
|isorulemax = B23c4-acn567/S08
|rle = true
|viewerconfig = #C [[ WIDTH 750 HEIGHT 500 TRACKLOOP 6 1 0 X -0.5 THUMBSIZE 3 ZOOM 32 GPS 2 ]]
|apgcode = xq6_1owo1z128821/b2s0
}}
'''Free ship''' is a common period-6 [[photon]] in {{rl|Live Free or Die}} which has a large [[tail spark]], and can be turned into [[puffer]]s. It emerges from the [[Domino]] sequence. There is a shorter variant of the free ship called the '''short free ship''', but it is rarer due to not evolving from the domino.
{{EmbedViewer
|rle = x = 8, y = 6, rule = B2/S0
o4bo$3b2obo$7bo$7bo$3b2obo$o4bo!
|viewerconfig = #C [[ THUMBSIZE 2 WIDTH 750 AUTOSTART GPS 2 TRACKLOOP 6 1 0 ]]
|position = center
|caption = Short free ship
|style = width:300px;
|apgcode = xq6_4q11q4z4y04/b2s0
}}

== Gallery ==
{{EmbedViewer
|rle = x = 11, y = 17, rule = B2/S0
2bo4bo$5b2obo$10bo$10bo$5b2obo$2bo4bo6$o4bo$3b2obo$8bo$8bo$3b2obo$o4b
o!
|viewerconfig = #C [[ THUMBSIZE 2 WIDTH 750 HEIGHT 400 ]]
|position = center
|caption = A [[Dot]] puffer consisting of two free ships
|style = width:300px;
}}
[[Category:Alien patterns]] [[Category:Alien spaceships]]

Apgcode

2026-07-26T00:59:41Z

SecondTypist: Corrected suffix information for linear growth

An '''apgcode''' is a unique identifier used by [[apgsearch]] and its search results database, [[Catagolue]], to classify and denote a [[pattern]]. A pattern's name may also be its apgcode (especially for small, otherwise unnamed patterns).

== Encoding objects ==
An apgcode consists of a prefix and a suffix, separated by an underscore. Both the prefix and the suffix are alphanumeric strings.

=== Prefix ===
The prefix consists of a two-character type and a number. For encodable objects, the types are:

* <tt>xs</tt> for a [[still life]];
* <tt>xp</tt> for an [[oscillator]];
* <tt>xq</tt> for a [[spaceship]];
* <tt>yl</tt> for a periodic linearly growing object, such as a [[puffer]] or [[gun]];
* <tt>methuselah</tt> for a [[methuselah]];
* <tt>messless</tt> for a [[diehard]]; and
* <tt>megasized</tt> for a soup with a large final population.

The number following the type represents the [[population]] for a still life, the lifespan for a methuselah or diehard, or otherwise the [[period]] of the object.
For an example, see [[xp2]].

Note that despite always having a constant shape and population, spaceships of period 1 are classified under <tt>xq</tt> rather than under <tt>xs</tt> or a dedicated period-1 spaceship prefix.

=== Suffix ===
In codes for <tt>xs</tt>, <tt>xp</tt>, and <tt>xq</tt>, the suffix following the underscore is a representation of the object in Extended Wechsler Format (see below).

In codes for <tt>yl</tt>, the suffix consists of additional information encoding higher-order periods of the pattern:<ref>https://conwaylife.com/forums/viewtopic.php?p=71429#p71429</ref>

* The first value is a number representing the "population growth" of the pattern, which is related to (but not necessarily identical to) the period. For example:
** Despite the [[block-laying switch engine]] having a period of 288, its value is 144 due to [[glide symmetry]].
** Likewise, a diagonal puffer from [[HighLife]] has a value of 960 rather than the expected 192 due to creating period-10 oscillators out of phase with each other.
* The second value represents the period at which the population of the debris fluctuates.
* The third value represents how much the population grows after the amount of generations specified in the first value have elapsed.
* The fourth value corresponds to the Extended Wechsler Format of the linear growth pattern.

=== Unencodable objects ===
In their original form, apgcodes are not guaranteed to encode still lifes, oscillators and spaceships exceeding a 40×40 bounding box.{{refn|group=note|Patterns exceeding a 40×40 bounding box can still be encoded using "classic" apgcodes if they match either fit within such a box in at least one phase, or if, alternatively, they do not contain runs of more than 39 zeroes in their extended Wechsler representation.}} These are instead reported by apgsearch and censused by Catagolue as ''oversized'' patterns, using the following types:

* <tt>ov_s</tt> for an oversized still life;
* <tt>ov_p</tt> for an oversized oscillator;
* <tt>ov_q</tt> for an oversized spaceship.

These types are then followed by a number representing the population for a still life, or otherwise the period of the object, as in the non-oversized case. apgcodes of this form do not uniquely identify a specific object, but rather represent classes of objects.

An extension to apgcodes, dubbed "greedy apgcodes" (see below), was later used to relax the 40×40 bounding box constraint, although some sufficiently large patterns remain canonically unencodable.

=== Unclassifiable objects ===
Objects which apgsearch cannot classify as above are denoted by one of:

* <tt>zz_EXPLOSIVE</tt>
* <tt>zz_LINEAR</tt>
* <tt>zz_QUADRATIC</tt>
* <tt>zz_REPLICATOR</tt>
* <tt>PATHOLOGICAL</tt> (e.g. high-period oscillators)

Chaotic-growth (<tt>zz_*</tt>) patterns are classified according to certain heuristics; the labels chosen do not necessarily reflect the nature of the object encountered, so an object classified as e.g. <tt>zz_REPLICATOR</tt> need not be an actual [[replicator]].

Like oversized apgcodes, these apgcodes do not uniquely identify specific objects.

== Extended Wechsler format ==
Non-oversized still lifes, oscillators and patterns are encoded in '''extended Wechsler format''', an extension of a pattern notation developed by [[Allan Wechsler]] in 1992.

* The pattern is separated into horizontal strips of five rows.
** Each strip, ''n'' columns wide, is encoded as a string of ''n'' characters in the set {<tt>0</tt>, <tt>1</tt>, <tt>2</tt>, ..., <tt>8</tt>, <tt>9</tt>, <tt>a</tt>, <tt>b</tt>, ..., <tt>v</tt>} denoting the five cells in a vertical column corresponding to the bitstrings {'00000', '00001', '00010', ..., '01000', '01001', '01010', '01011', ... '11111'}.
** The characters '<tt>w</tt>' and '<tt>x</tt>' are used to abbreviate '<tt>00</tt>' and '<tt>000</tt>', respectively, and the symbols {'<tt>y0</tt>', '<tt>y1</tt>', <tt>y2</tt>', ..., '<tt>yx</tt>', '<tt>yy</tt>', '<tt>yz</tt>'} are used to encode runs of between 4 and 39 consecutive '<tt>0</tt>'s.
** Extraneous '<tt>0</tt>'s at the ends of strips are not included in the encoding. (Note that in particular, blank five-row strips are represented by the empty string.)
* The character '<tt>z</tt>' separates contiguous five-row strips.

=== Examples ===
<tt>xq4_27deee6</tt> encodes a [[heavyweight spaceship]]:

[[File:xq4 27deee6 annotated.png|center]]

<tt>xs31_0ca178b96z69d1d96</tt> encodes a 31-bit still life; note how the '<tt>z</tt>' separates the two five-row strips:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em;" | [[File:xs31 0ca178b96z69d1d96 annotated strip1.png|center]]
|-
| style="padding-bottom: 0.5em;" | [[File:xs31 0ca178b96z69d1d96 annotated strip2.png]]
|}

<tt>xp30_w33z8kqrqk8zzzx33</tt> encodes a [[trans-queen bee shuttle]]; note how five-row strips are represented by the empty string:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em;" | [[File:Xp30 w33z8kqrqk8zzzx33 annotated strip1.png|center]]
|-
| style="padding-bottom: 0.5em;" | [[File:Xp30 w33z8kqrqk8zzzx33 annotated strip2.png|center]]
|-
| style="padding-bottom: 0.5em;" | <center>(10 blank rows omitted)</center>
|-
| [[File:Xp30 w33z8kqrqk8zzzx33 annotated striplast.png|center]]
|}

<tt>xp2_31a08zy0123cko</tt> is a [[quadpole tie ship]]; note how trailing zeros in the first five-row strip are not encoded:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em;"| [[File:xp2 31a08zy0123cko annotated strip1.png|center]]
|-
| [[File:xp2 31a08zy0123cko annotated strip2.png|center]]
|}

== Canonical form ==
In order to enforce a canonical form, there are further rules regarding encoding:

* The leftmost column and uppermost row must each contain at least one live cell. (This gives a canonical position.)
* A canonical orientation and phase must be determined. For example, with the [[caterer]] (p3 oscillator with no [[symmetry]]), there are three phases and eight orientations, so we have 24 possible encodings. A total order on these encodings is defined as follows:
** Shorter representations are preferred to longer representations;
** For representations of the same length, lexicographical ASCII ordering is applied, and preference given to earlier strings.

This gives, for any still-life, oscillator or spaceship, an unambiguous canonical code to represent the pattern. It has several desirable properties:

* Compression: it is much more compact than [[RLE]] or [[SOF]] for storing very small patterns, and sometimes even beats the common name ('<tt>xp15_4r4z4r4</tt>' is shorter than '[[pentadecathlon]]')!
* Character set: it only uses digits, lowercase letters and the underscore, so can be safely used in filenames and URLs.
* Human-readability: the prefix means that we can instantly see whether a particular object is a still-life (and if so, what size), oscillator (and if so, what period) or spaceship (and if so, what period). It also means that the string is instantly recognised as being an encoding of an object ('<tt>xp2_7</tt>' is obviously a [[blinker]], whereas the digit 7 on its own with no extra context is ambiguous).

== Adapting apgcodes to larger patterns ==
As apgcodes were originally limited to patterns fitting into a 40×40 bounding box, different ways of extending them to allow unambiguously encoding larger patterns were proposed.<ref name="forumthread2307" /> In their original form, apgcodes are not guaranteed to be able to encode larger patterns, due a lack of well-definedness for runs of 40 or more consecutive zeroes, and apgsearch versions up to 3.x would report such patterns as oversized instead of attempting to encode them.

Extended ("greedy") apgcodes were eventually adopted to allow larger patterns to be encoded. These avoid the problem by stipulating that a run of ''n'' zeroes be encoded as follows:

# If ''n'' is less than 40, the run is encoded as in regular apgcodes, using the characters <tt>w</tt>, <tt>x</tt>, and <tt>y0</tt> .. <tt>yz</tt> as appropriate.
# If ''n'' is equal to or greater than 40, the run is encoded as <tt>yz</tt> (representing the first 39 zeroes), following by the encoding for a run of ''n'' - 39 zeroes according to this definition.

That is to say:

:[[File:Extended apgcodes zeroes encoding.png]]

This extension, which is used on the LifeWiki for larger patterns, retains compatibility with existing apgcode decoders. Adapting encoders to produce extended apgcodes is similarly straightforward.

Greedy apgcodes were adopted for [[apgsearch]] 4.x<ref name="post48682" />, subject to the following constraints:

* (width + 2) * (height + 2) <= 10000;
* the resulting apgcode, without the prefix, cannot exceed 1280 bytes.

== Adapting apgcodes to multistate rules ==
Work is ongoing on extending apgcodes to multistate ([[Generations]]) rules.<ref name="post47999" /> For this, apgcodes encoding still lifes, oscillators and spaceships will contain multiple suffixes, separated by underscores.{{refn|group=note|That is to say, these apgcodes will match the following regular expression: <tt>x[spq][0-9]+(_[0-9a-z]+)*</tt>}}

Each suffix will encode one 'layer' of the pattern, with patterns in an ''n''-state rule having 2+&lceil;log2(''n''-2)&rceil; layers, where layer 0 is 'live', layer 1 is 'refractory', and the remaining layers implement a binary counter.

More precisely, a pattern in an ''n''-state [[Generations]] rule is represented as follows:<ref name="post49788" /><ref name="post49793" />

# "Dying" states are renumbered to 2, 6, 10, 14, 18, ..., in reverse chronological order.
# Each state is represented as a binary number.
# An extended Wechsler representation is generated for each bit position, starting with the least significant bit.
# The resulting representations, now called "layers" are concatenated with underscores to form a representation of the entire pattern.

To obtain the pattern's canonical object, representations are generated for each phase and each possible orientation of the pattern, and the canonical representation is chosen as described in the "Canonical form" section above. Finally, a suitable prefix describing the pattern's overall behavior is prepended.

In 3-state rules, this simplifies to the two layers directly representing cell states 1 and 2, respectively.

=== Examples ===
For example, the following spaceship in [[Brian's Brain]] ([[Generations]] rule /2/3, aka B2/S/G3) is represented by the apgcode <tt>xq4_3482h8a_03482lx8</tt>:

{{EmbedViewer
|apgcode = xq4_3482h8a_03482lx8/g3b2s
|position = center
|viewerconfig = [[ GRID GRIDMAJOR 0 GPS 2 AUTOSTART THUMBLAUNCH THUMBSIZE 2 TRACKLOOP 4 -1 0 COLOR 2 128 128 128 ]]
|rle =
x = 11, y = 5, rule = /2/3
AB2.AB$AB.AB$.AB.A4.B$2.AB4.A.B$4.AB2.B!
}}

As [[Brian's Brain]] is a 3-state rule, the two layers of the code directly represent cells in states 1 (live) and 2 (dying); note how <tt>x</tt> represents <tt>000</tt> in the second layer:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em; padding-right: 0.5em" | [[File:xq4 3482h8a 03482lx8 layer1 annotated.png]]
| style="padding-bottom: 0.5em; padding-left: 0.5em" | [[File:xq4 3482h8a 03482lx8 layer2 annotated.png]]
|}

Putting both layers together yields the complete pattern:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em;" | [[File:xq4 3482h8a 03482lx8 annotated.png]]
|}

For a more complex example, consider the following [[reflectorless rotating oscillator]] in an 11-state [[Generations]] version of [[Conway's Game of Life]] (23/3/11), <tt>xp32_ss2gzw11_wsfm76cg_x86668_wke2024_ws6i1_x1</tt>:

{{EmbedViewer
|apgcode = xp32_ss2gzw11_wsfm76cg_x86668_wke2024_ws6i1_x1/g11b3s23
|position = center
|viewerconfig = [[ GRID GRIDMAJOR 0 GPS 16 AUTOSTART THUMBLAUNCH THUMBSIZE 2 LOOP 32 WIDTH 640 HEIGHT 640 ZOOM 32 ]]
|rle =
x = 9, y = 6, rule = 23/3/11
3.B.F$2.ADCIG$2A2D3IH$2AFG3.I$2ADAF3.J$2.2A!
}}

In order to encode this pattern, states 2, 3, ..., 10 are renumbered 34, 30, ..., 6, 2; six layers are then used to encode each bit of these new state numbers:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em; padding-right: 0.5em" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 layer1 annotated.png]]
| style="padding-bottom: 0.5em; padding-left: 0.5em; padding-right: 0.5em" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 layer2 annotated.png]]
| style="padding-bottom: 0.5em; padding-left: 0.5em; padding-right: 0.5em" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 layer3 annotated.png]]
| style="padding-bottom: 0.5em; padding-left: 0.5em; padding-right: 0.5em" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 layer4 annotated.png]]
| style="padding-bottom: 0.5em; padding-left: 0.5em; padding-right: 0.5em" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 layer5 annotated.png]]
| style="padding-bottom: 0.5em; padding-left: 0.5em;" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 layer6 annotated.png]]
|}

Putting the layers together yields the complete pattern:

{| style="margin-left: auto; margin-right: auto;"
|-
| style="padding-bottom: 0.5em;" | [[File:xp32 ss2gzw11 wsfm76cg x86668 wke2024 ws6i1 x1 annotated.png]]
|}

== Long-lived soups ==
Unlike with other patterns, apgcodes for [[methuselah]]s and [[diehard]]s classify the soup itself rather than the individual objects that emerge from it, and do not convey any information other than the soup's lifespan.

Ordinary methuselahs are classified under the <tt>methuselah</tt> prefix with the suffix being the soup's lifespan with the last three digits truncated and the letter <tt>k</tt> to stand for "thousand." For example, [[42100M]] was recorded by [[apgsearch]] as <tt>methuselah_42k</tt>, and is therefore collected by [[Catagolue]] with all other soups lasting between 42,000 and 42,999 generations.{{refn|group=note|Only methuselahs lasting at least 25,000 generations are reported by apgsearch, and only by versions v4.54 or later. Additionally, apgsearch estimates the lifespan of each soup before testing it more precisely, and is not guaranteed to detect all <tt>methuselah_25k</tt> soups.}}

Diehards, or long-lived soups which leave behind no [[ash]], are classified similar to other methuselahs, but under the <tt>messless</tt> prefix. Only two digits are truncated for messless soups and replaced with the letter <tt>h</tt> to stand for "hundred."{{refn|group=note|Only diehards lasting at least 500 generations are reported by apgsearch, and only by versions v4.69 or later.}}

Soups with large final populations are classified under the <tt>megasized</tt> prefix. Like with diehards, two digits are truncated from the population count.{{refn|group=note|Only soups with final populations of at least 3,000 are reported by apgsearch, and only by versions v5.03 or later.}}

== Limitations ==
An apgcode does not encode the rule with the pattern. An apgcode can be ambiguous if a rule is neither specified nor implicitly assumed, with the same code being assigned to different patterns evolving differently. For example, the code <tt>xp2_2a54</tt> describes at least three different period-2 oscillators in outer-totalistic rules which are all titled as "[[clock]]"; further variants exist in [[non-totalistic cellular automaton|non-totalistic rules]]:

{| style="margin-left: auto; margin-right: auto;" class="wikitable"
|+ Evolution of xp2_2a54 across different rules
|-
| align="center" | [[File:Xp2 2a54 b3s23.gif]]
| align="center" | [[File:Xp2 2a54 b34s.gif]]
| align="center" | [[File:Xp2 2a54 b4s1.gif]]
|-
| B3/S3 to B35678/S02345678
| B34/S to B345678/S0245678
| B4/S1 to B45678/S01245678
|}

Apgcode was not designed to encode arbitrary patterns in an unambiguous way (including infinite growth patterns and active regions).<ref>{{LinkForumThread|p=132285|title=Re: Thread for basic questions|format=ref}}</ref> The exact location and orientation of a pattern and the specific phase of a periodic pattern are not encoded in an apgcode.<ref>{{LinkForumThread|p=132288|title=Re: Thread for basic questions|format=ref}}</ref>

== See also ==
* [[Catagolue naming conventions]]
* [[File formats]]

== Notes ==
<references group="note" />

== References ==
<references>
<ref name="forumthread2307">{{LinkForumThread
|f = 7
|t = 2307
|title = Extending apgcodes to larger patterns
|format = ref
|author = Apple Bottom
|date = July 25, 2016
}}</ref>
<ref name="post47999">{{LinkForumThread
|p = 47999
|title = Re: apgsearch v3.1
|format = ref
|author = Adam P. Goucher
|date = August 4, 2017
}}</ref>
<ref name="post48682">{{LinkForumThread
|p = 48682
|title = Re: Extending apgcodes to larger patterns
|format = ref
|author = Adam P. Goucher
|date = August 12, 2017
}}</ref>
<ref name="post49788">{{LinkForumThread
|p = 49788
|title = Re: Catagolue browser extension
|format = ref
|author = BlinkerSpawn
|date = August 24, 2017
}}</ref>
<ref name="post49793">{{LinkForumThread
|p = 49793
|title = Re: Catagolue browser extension
|format = ref
|author = Adam P. Goucher
|date = August 24, 2017
}}</ref>
</references>

{{CatagolueNavbox}}

[[Category:Everything else]]
[[Category:File formats]]
[[Category:Algorithms]]

{{DISPLAYTITLE:apgcode}}