https://cs.uwaterloo.ca/~csk/hat/app.html
I just wished one could turn off the colors.
The colors really distract me from trying to see the patterns the shape itself creates. For me, the beauty here is that each piece is exactly the same. Colorizing them differently takes away from that.
main { filter: saturate(7) grayscale(10) contrast(3); }
It's not too hard to scrape the JavaScript out of the page. You could figure out where they set the colors and change that part.
I also wonder if you can do that on https://mathigon.org/polypad/8kVqVH2Mor6JTQ
There's also https://cs.uwaterloo.ca/~csk/hat/, but sadly I didn't see anything like a github link to the above demo.