Hi Elliot,
Thanks for the email. It does look like blocks is broken right now. That's news to me, and I hope to find the time to figure out what happened soon. It is intended to still work. If you have time to look into it, I'd suggest starting by bisecting the failure in git history to find the commit that broke it. I probably won't get to that until this weekend, if I'm being honest.
After it's working again, there are still significant challenges to bringing the project to a usable state. There are a number of open bugs involving inconsistent state and type inference, which defeated the project the first time around. It's an interesting proof of concept, but I'm afraid it's not really production-ready. It has been stalled since Stefan's Summer of Haskell project in 2016. I did teach with it one semester (4th and 5th grades, so ages 9-11 years) without running into big problems, but I wouldn't feel confident in it. So aside from fixing the current broken state, I suspect what it needs most is an owner with a vision for the project and time to get it there.