floor · mod · a single enormous integer

Tupper.

A whole picture lives inside one number. Plot the inequality ½ < ⌊mod(⌊y/H⌋·2−H⌊x⌋−mod(⌊y⌋,H), 2)⌋ and the bits of that number become pixels. Draw on the grid to build the number, or change H (the famous “17”) to warp the encoding.

column stride + rows
⌊k/H⌋
k — the number that draws itself 0 digits ·
0
paste a k to plot it

How it reads: pixel at column x, row y turns on when bit H·x + y of ⌊k/H⌋ is 1. The published constant assumes bit 0 = top-right and y running downward — that’s why Flip X and Flip Y start on. In draw mode the number is rebuilt from your pixels exactly, so the round-trip is always faithful.