Similar to https://www.chesspuzzles.com/mate-in-three, is there a website that presents you with some prewritten code that you can edit slightly to get the desired result?
This is not quite what you're asking for, but it's in the spirit of what you want:
<a href="https://en.m.wikipedia.org/wiki/Shenzhen_I/O" rel="nofollow">https://en.m.wikipedia.org/wiki/Shenzhen_I/O</a>
<a href="https://codingdojo.org/" rel="nofollow">https://codingdojo.org/</a><p>Or try the games of Tomorrow Corporation and Zachtronics.