This is similar to how I create card games or board games (just a hobby). It's a wonderful feeling when different elements come together. For example, I translate rules from a sport to bridge cards, see if they work better when you add tokens, a board or gambling, with two or more players, with meta-rules for changing the rules, and in the end, a new game emerges.
Writing nonfiction is more straightforward, I don't need inspiration for that. I do write down my dreams, though.