Ask HN: Do you have weird “puzzle dreams” after a day of abstract programming?

Here's something I noticed about myself and later had confirmed by a few colleagues: After a day of programming abstract concepts (pure algorithms, math-heavy things etc.) my dreams are upsetting. I wouldn't strictly call them nightmares, but I dream of boxes folding into each other or cranks, pushing and pulling. My colleagues told me about similar dreams, involving gears, folding paper, pyramids, and other geometric shapes. My theory is that our brain tries to process the events of the day in a non-concrete fashion - and abstract programming gives it little to work with. But I am wondering: How widespread is this phenomenon? Do other people experience the same?