This has to be one of the coolest retro-hardware projects I’ve seen in a while. It’s a transistor-level simulator of the 6502, written in Javascript, that visually simulates the device based on its original mask pattern — painstakingly reverse-engineered from high-resolution die photographs.

And

It makes my head spin to think that the CPU from the first real computer I used, the Apple II, is now simulateable at the mask levelas a browser plug-in.