Truchet tiles are cute. They were first thought up by Sebastien Truchet way back in 1704.
Randomly tiling an area with and the same object rotated 90° or 270° results in wonderful things.
I bet Sebastien would have loved a computer.
Here is an area paved entirely with the one tile all lined up the same way.
Click the buttons below to change them.
Weirdly, this stuff finds applications in modeling magnetism, boiling water, and all kinds of natural things.