I haven’t explored this as far as I’d need to to know where to guide you next. The loops are interesting, though, and represent their own “end.” I wonder if powers of 2 are the shapes that will end in zeroes – have you tried octagons?

The images are really key 🙂

Very helpful! I didn’t realize the inner squares became diagonal to the original square and so I had competing grids that got super confusing. Thanks so much!

Some of the original images in that blog post got corrupted at some point. But yes – there’s a video here: https://youtu.be/pk1zwq1xLq4

And an updated blog post about diffy squares here: https://mathforlove.com/2020/03/diffy-squares/

I hope that helps!