Mark’s taken something old, added something new, and retained the spirit of the cartridge’s original use, so you get the Proustian rush of wasted 1990s afternoons when you pick it up. He’s even added a Pimoroni LED SHIM to the display, for a bonus rainbow effect.
The materials for the build cost about £30 from your local internet retailer, and Mark has documented the build here: hsmag.cc/UOIQuJ.