The latest in emergent tiling;
laid down at random on a floor of your choice, each double-sided tile
will compare itself to its neighbours and flip itself over if it finds itself orthogonally
adjacent to more than one of the same colour.
(If you're wondering, a "flip over if adjacent to any of same colour" rule is doomed, because any clusters of checkerboard that successfully emerge are immediately consumed by doubt at the edges, and collapse in on themselves. Press 'z' to flip between this and the normal rule, to see for yourself.)