It's been a while since I designed a PCB, so here goes. I actually finished this one 2 weeks ago, but some people on the Kicad discord told me about power/ground loops and I decided to redo the traces from scratch.
It's supposed to be a PCB you can stack in a grid, which communicates with UART to each neighboring PCB. Each panel will have a grid of LEDs on the front (not pictured here), and they should be able to run their own Game of Life logic, which should make it infinitely expandable.