I think this has lots of potential, great work. You might wanna stop or warn when the script takes a while to run, I tried running lesson 2 with range(30) and

I think this has lots of potential, great work. You might wanna stop or warn when the script takes a while to run, I tried running lesson 2 with range(30) and it crashed the page (Mac/Chrome). Putting a save button on the header might avoid some confusion too.