Thanks Tyler Berbert for the submission!
While it was made by a student trying to solve a student problem, I’m beginning to think there has been nothing created since the internet that could help teachers more than Piazzza.
If you know anyone teaching over the summer, consider it an obligation as a citizen to introduce this colleague to it. It’s free. Here’s a pretty good article about it, and here’s something I wrote about it. So yeah. Enjoy!