I love this write-up, especially the interactive diagrams at the end. My vid doesn't go into as much detail on the actual circuit design, but like the article it uses a bunch of BCD ripple-carry adders. For output I use standard 7-segment decoders. As noted in the comments there are faster ways to do logic in Quake which I overlooked in my research, but to my knowledge noone has made a circuit this large before. I've put the source code on github for anyone that wants to take a deeper look: https://github.com/matthewearl/q1logic/