A neat puzzle that I always liked as a kid is a maze. I liked tracing the paths with a pencil to find a solution, but I also liked drawing mazes myself. Usually then of course orthogonal walls on a squared paper.
Later on I started to work a little bit with backtracking algorithms, which create and solve mazes by themselves. But in the course of this I never got beyond the orthogonal form.
On the net you can find some tools with which you can create very varied mazes. In many cases, these are already vector graphics that can be plotted directly and, as I find, have quite aesthetic value beyond the functional use. For private use free and really very flexible is mazegenerator.net. But at GitHub you can find literally hundreds more programs that generate mazes - in all kinds of programming languages.
I liked Maze which also allows crossings. To give the results a final twist, you can use Illustrator to implement distortions that change the look significantly and make the solution much more difficult.