Day & Night

Day & Night is a cellular automaton related to the Game of Life, invented by Nathan Thompson in 1997. Its rule notation is 34678/3678. The rule is given the name "Day & Night" because the 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.

External links

• Day & Night – An Interesting Variant of Life (zip file)