I once made a small x86 asm program that generated an image with a similar technique, except with 1-bit colour. Instead of x ^ y, it was parity(x ^ y), i.e. if there are an even number of 1 bits, colour it one way, else colour it another. It had an interesting visual effect; it looks like a tiling that almost repeats but not perfectly.

Edit: Just looked through some old files and found the program. It was written in fasm in 2019 and generates an XPM2 file (which I had to manually convert to XPM3 to view). Here's the resulting image: https://i.postimg.cc/FsFhXSHG/xortiles.png

(I can post the code if anyone wants, though I don't know why you'd care.)