Some image experiments...

This starts from a random image and computes the average of the colors around a pixel and then sets the new color of the pixel to the most distant color from the average color in neighboring pixels.

This starts from a random image and takes random marches from each pixel until it finds the starting pixel color and then color the path taken in this color.

This is a plot of the greatest common divisors (gcd) of pairs of integers. Coprime integers are colored in black (their gcd is 1).

Notice how prime numbers are numbers such that the corresponding row/column is white all the way to the diagonal ! (They should be black but I chose to make them white to make them stand out). It means such numbers have a gcd of 1 with any other lower integer.