Thank you. I'm really glad the visuals worked.
To answer your question, I first started by thinking about how I would teach players new mechanics without getting wordy. In those instances, I deliberately made them small and mainly linear so that players would could understand the mechanics more clearly without feeling overwhelmed or lost (I hope achieved that, anyway).
As for the puzzles that came after those tutorials, I try to envision a desired route and then add branching paths like in a maze. Other times, I often just play around with the blocks randomly until I find something I like and work with it. You might have noticed, but several of the levels I designed form a checkerboard pattern, which I found eases my design process as I don't feel as obligated to make every step be a shape tile. That's part of why I made the blank tiles and programmed the game to not register that when looping through the given sequence of shapes.
Sorry if I was being too wordy. I'm just passionate about games and puzzles, so I couldn't help myself.
I hope this explains my process. Thanks for stopping by. :)