To celebrate the 256th image uploaded to allRGB, here is a collage of the first 256 uploads (including this one!), thumbnailed to 256×256 pixels each with a random sampling algorithm.
While the pool of undrawn colors is nonempty, pick one at random, find its location in the thumbnail of a random one of the 255 existing images, and draw it there. If another color was already drawn there, bump that color to the corresponding location in the thumbnail of _this_ image, and so on. Colors bumped from the upper-left pixel (which corresponds to itself) move back into the pool to be redrawn later.
https://github.com/andersk/allrgb
