More than two thousand years ago, Eratosthenes of Cyrene found the primes by crossing numbers out using a simple process: Remove every multiple of 2, then of 3, then of 5, and so on. Whatever survives can be divided only by itself and one. In this print every number is a dot: the pale ones crossed out, and the colored ones are prime.

If you write the numbers in rows, the width of the row decides the picture.

Prime Numbers. Rows 751 numbers wide. 751 is itself prime, and each row is one longer than 750, so the stripes made by 2, 3 and 5 slip one place every row into diagonals.