The image on the cover of this book is derived from the first 440 or so steps (with perhaps 10 at each end cut off by trimming) of the pattern generated by evolution according to the rule 110 cellular automaton discussed on page 32, with an initial condition consisting of repeats of followed by repeats of . The picture on the right shows 3000 steps in this evolution. The central region grows by 1 cell every 2 steps on the left and 22 cells every 340 steps on the right. Many persistent structures emanate from the right-hand edge of the region. After just 29 steps, this edge takes on a form that repeats every 1700 steps. During each such cycle, a total of 65 persistent structures are produced, of 11 of the 15 kinds from page 292, and their interactions make the full repetition period 6800 steps.