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 twenty-two spaceship velocities have been constructed, including four infinitely adjustable families of ships?
- ...that there are 71 distinct ways for two gliders to collide, but it is unknown how many distinct 3-glider collisions there are?
- ... that to display the smallest known gun pattern for a Gemini spaceship at 1 cell = 1 pixel, on a standard-density video monitor, a screen over one mile square would be needed?
- ... that no odd-period glider guns were known before 1995, when a period 565 p5-spark-assisted B-heptomino loop was constructed by David Buckingham?
- ... that even though the speed limit for spaceships is c/2 in a vacuum, in a medium of stripes agar there are "spaceships" that can travel at lightspeed along the stripes, or two thirds of lightspeed perpendicular to the stripes?
- ... that the smallest known spacefiller pattern consists of 187 cells?
- ... that the smallest known sawtooth pattern in Conway's Life consists of only 177 ON cells?
- ... that there are now over a hundred and twenty known Herschel conduits, counting stable conduits only, and a much larger number if oscillator-supported conduits are included?
- ... that Demonoids, caterloopillars and half-bakery knightships are the only known types of spaceships with fixed slope but adjustable speed?
- ... that a pattern exists in which no cell in the unbounded Life plane ever becomes periodic?