I've thought about building something similar 100 times. So happy to see someone do it! I have a daily habit of doing math problems, just to keep the various br

I've thought about building something similar 100 times. So happy to see someone do it! I have a daily habit of doing math problems, just to keep the various branches I've studied somewhat fresh in my mind, and finding good problem sets that can be accessed easily has been a surprisingly hard challenge. If you're interested in open sourcing it so collaborators can help contribute to some of the future features you've discussed in the thread here, let us know! I'm sure there are plenty of people who'd like to pitch in.