has gloss | eng: Day & Night is a cellular automaton in the same family as Game of Life, defined by rule notation 34678/3678. It was invented and named by Nathan Thompson in 1997, and investigated extensively by David I. Bell. The rule is given the name "Day & Night" because its on and off states are symmetric: if all the cells in the Universe are inverted, the future states are the inversions of the future states of the original pattern. A pattern in which the entire universe consists of off cells except for finitely many on cells can equivalently be represented by a pattern in which the whole universe is covered in on cells except for finitely many off cells. |