I was running an afterschool program teaching kids to code and we were looking for a way to have them code that was more social and group oriented rather than having everyone hunched over a computer more or less by themselves all the time. I was also looking for a project to explore Computer Vision and Machine Learning. This ended up being a good fit for both needs. The video on the website shows the students working on it. It's surprisingly engaging for being just paper cards you are writing on...
If you want to try it out and don't want to register via the website you can email me at my first name (jared) at puzzleschool.com and I'll send you the zip file containing the cards and a few sample programs that can be printed out and photographed directly.