This week's featured article
| A polyomino (or simply omino) is a finite collection of orthogonally connected cells. Conway's early investigations of Life and other cellular automata involved tracking the histories of small polyominoes, this being a reasonable way to ascertain the typical behaviour of different cellular automata when the patterns had to be evolved by hand rather than by computer. Polyominoes have no special significance in Life, but their extensive study during the early years lead to a number of important discoveries and has influenced the terminology of Life.
It is possible for a polyomino to be an oscillator. In fact, there are infinitely many examples of such polyominoes, including the cross and its larger analogues. The only other known examples are the block (which has period 1), the blinker, the toad, the star and (in two different phases) the pentadecathlon.
A polyomino can also be a spaceship, though the only known examples are the lightweight spaceship, the middleweight spaceship, and the heavyweight spaceship.
| The LifeWiki contains one of the most comprehensive catalogues of patterns available on the internet. Within it you will find:
Did you know...
- ... that an N-bit strict still life – specifically, some length of long long (...) boat or barge – can be constructed for any odd integer N using no more than 39 gliders, and for any even integer N using no more than 38 gliders, using a temporary tubstretcher?
- ... that an N-bit period-2 oscillator can be constructed for any odd integer N using no more than 45 gliders, and for any even integer N using no more than 46 gliders, using a temporary tubstretcher?
- ...that it is currently an open question as to if there exists a periodic pattern whose only predecessors are its own evolutionary sequence?
- ...that it can be proved reflectorless rotating oscillators exist in Life, although none have yet been found or constructed?
- ...that there are currently known elementary spaceships with speeds c/7 and c/10 orthogonal, but none with c/8 or c/9?
- ... that the largest interesting pattern constructed, the caterpillar, contains over 11 million cells?
- ... that the Gosper glider gun was the first pattern to be discovered that exhibits infinite growth?
- ... that the block-laying switch engine and the glider-producing switch engine (and various combinations of two switch engines) are the only infinitely-growing patterns that are known to have ever occurred naturally from an asymmetric random starting configuration?
- ... that oscillators are known that oscillate at all periods other than 19, 23, 34, 38 and 41?
- ... that the pentadecathlon and the blinker are the only known oscillators that are polyominos in more than one phase?