3 ms·

a quick Internet also reveals: life:{3=a-x*4=a:2{+(0+':x)+1_x,0}/x}

• beagle3 13y ago
  Explantion: x is a 0/1 matrix of live cells. 0+':x -> "sum each element with one to the left (0 left of the first)" 1_x,0 -> "drop first, add zero at the end" (0+':x)+1_x,0 -> "sum each element with the one to the left and the one to the right (sum of previous expressions)" a:2{+...}/x -> "do that; transpose; do that; transpose again, and assign to a. 2{}/ means 'do twice'" At this point, "a" has the same shape of "x", but in every element is the sum of the elements of x from that location, one above, one below, one left, and one right. 4=a -> "1 where a=4, 0 otherwise" x*4=a -> "1 where x is 1 and a=4, 0 otherwise" a-x*4=a -> "decrease a from 4 to 3 if x=1 in the that place" 3=a-x*4=a -> "1 where one has 3 neighbours" So, if x is a 1/0 matrix "life x" does one iteration of Conway's game of life. And "1000 life/ x" would seek convergence or return to first state (but no more than 1000 iterations). There is code golfing here; It would have been purely readable K code if it wasn't golfed. But it would also have been two to three times as long.