For anyone interested: Here's an ambiguous set of instructions (in the spirit of Sol leWitt or https://conditionaldesign.org) for (re)creating a simplified version of the infinitely evolving De/Frag piece (see beginning of this thread).
Preparations:
0) You may use any suitable medium.
1) Create a pixel-based canvas of arbitrary dimensions.
2) Create a palette of random choice of 4 colors, plus black and white.
Repeated steps:
3) Choose two random colors from the palette, giving black or white priority.
4) Using the chosen colors, create a random pixel pattern in one of four sizes (e.g. using percentages of the longest side of the canvas as pattern size, e.g. 1%, 2%, 5%, 10%, or 4x4, 8x8, 16x16 pixels...)
5) Choose a random pixel position on the canvas and a random color tolerance.
6) Perform the flood fill algorithm[1] from the chosen start position, selecting all connected pixels within the chosen tolerance.
7) Apply the new pattern (created in step 4) to the pixels selected in step 6, in an order and speed of your choosing.
8) Repeat from step 3
[1] The Flood Fill algorithm is described here:
https://en.wikipedia.org/wiki/Flood_fill