OCA:DryLife
| DryLife | |
| Rulestring | 23/37 B37/S23 |
|---|---|
| Rule integer | 6280 |
| Character | Explosive |
| Black/white reversal | B0123478/S0234678 |
DryLife is a Life-like cellular automaton in which cells survive from one generation to the next if they have 2 or 3 neighbours, and are born if they have 3 or 7 neighbours. The rule behaves in an explosive manner, as small patterns, such as the stairstep hexomino, may exhibit chaotic growth.
Behavior
As mentioned before, DryLife is an explosive rule, which is caused by small patterns exhibiting infinite growth, most notably the stairstep hexomino and from there lumps of muck. Some patterns, like the R-pentomino, Pi heptomino, and Herschel, actually end up being less active in this rule than they are in Life.
Ash in exploding soups are similar to Life, with most of the common objects along with some constellations, including those specific to this rule. Many escaping gliders can also be seen.
Patterns
Still lifes
All still lifes from regular Life work in DryLife, as B7 does not impact still lifes. The cis-mirrored bun is notably more common due to a constellation containing them. This constellation is the "flower garden", a common constellation composed of two cis-mirrored buns along with two bi-boats. It evolves from some honey farm predecessors like bun.
| The flower garden (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
There is another common alien constellation in DryLife, consisting of just two tubs. It mainly evolves from the Pi-heptomino.
| The pi-heptomino evolving into a two-tub constellation (click above to open LifeViewer) |
Spaceships and puffers
DryLife is so named because the standard spaceships from normal life; lightweight spaceship, middleweight spaceship, and heavyweight spaceship — also known as "fishes" — do not work, though the glider does. Some other spaceships, such as the x66, weekender and loafer, work in this rule. The copperhead evolves into the closely related c/10 goldenhead, differing from copperhead by two cells in one phase, and it supports the pseudo-tagalong in fireship as well.
| Goldenhead (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
A pair of correctly spaced B-heptominoes (as in the twin bees shuttle) evolves into a messy period-160 c/2 orthogonal puffer. It is also gutter-symmetric.
| B-heptomino puffer (click above to open LifeViewer) RLE: here Plaintext: here |
| A 2-engine 9c/28 spaceship found by Paul Tooke (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
A new speed allowed by DryLife is 9c/28 orthogonal. Technology travelling at this speed relies on the R-pentomino. Two R-pentominoes constitute a small symmetric 9c/28 orthogonal pond puffer, or a spaceship. A 3-glider collision that synthesises a R-pentomino via beehive works well, so guns and breeders have been constructed that fire spaceships and rakes of this speed respectively.
Oscillators
Many common oscillators, like blinker and toad, still work under DryLife's rules. The pulsar is slightly more common.
Queen bee shuttles do not work, as the queen bee evolves much differently and doesn't copy itself.
One noteworthy alien oscillator is a small period-32 reflectorless rotating oscillator called spinner, which gives banana sparks and is therefore capable of reflecting gliders by 90 degrees. Jason Summers found that a collision between a glider and a half-open twirling T-tetsons 2 produces two 90-degree gliders while sustaining the pre-pulsar engine, resulting in a period-60 glider gun; a blocker and a spinner can be added as filters for a p480 gun.
| Spinner (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
Universality
There is a proof sketch of DryLife's universality on ConwayLife.com forums. It is a proof-scheme covering all rules in the outer-totalistic rulespace between B3/S23 and B3678/S23678.[1]
In 2018, Peter Naszvadi constructed an explicit Rule 110 unit cell in DryLife, proving its Turing-completeness.[2] The pattern itself is basically a meta-polyglot, covering some related cellular automata in which the pattern only differs in some parts (in this case, the guns).
See also
- DryLife without death (B37/S012345678)
- Grounded Life (B35/S23), which does not support the glider along with the xWSSes
- PiLife (B37eS23)
References
- ↑ Peter Naszvadi (December 12, 2016). Re: List of the Turing-complete totalistic life-like CA (discussion thread) at the ConwayLife.com forums
- ↑ Peter Naszvadi (March 29, 2018). Re: List of the Turing-complete totalistic life-like CA (discussion thread) at the ConwayLife.com forums
External links
- DryLife at Adam P. Goucher's Catagolue
- Puffer with unstable trail (B37/S23) (discussion thread) at the ConwayLife.com forums
- DryLife Exploration Thread (discussion thread) at the ConwayLife.com forums
- Taming B37/S23 (discussion thread) at the ConwayLife.com forums
- DryLife at David Eppstein's Glider Database