If you haven't, read the info in the previous pic, too. There's also a nicer closeup pic of that LED panel on Bill Buzbee's HomebrewCPU at his site here. I asked after getting some info from him if the terminal next to it was connected to the computer he'd built from scratch, and he said yes, and then typed in some commands, and up fired a version of Conway's "Game of Life," all while the red LEDs on the homebuilt computer lit up, tracking registers, and serving out the info. The game played back at about 1.5FPS, which I find amazing. Definitely read what he did at his site. Here's a preview:
"Magic-1 is a homebuilt minicomputer. It doesn't use an off-the-shelf microprocessor, but rather has a custom CPU made out of 74 Series TTL chips. Altogether there are more than 200 chips in Magic-1 connected together with thousands of individually wrapped wires. And, it works. Not only the hardware, but there's also a full ANSI C compiler for Magic-1 (retargeted LCC), and a rudimentary homebrew operating system."