Background [in rule 110]

At every step the background pattern in rule 110 consists of repetitions of the block b = {1,0,0,1,1,0,1,1,1,1,1,0,0,0}, as shown in the picture below. On step t the color of a cell at position x is given by b〚Mod[x + 4 t, 14] + 1〛.