Same here actually, I was imagining a mosaic of little Piet programs all run in parallel on a GPU. The time I spent with Piet was pretty rewarding. I did a project where I took my company's phone screen interview question and completed it in esoteric languages. Piet was the most fun of the challenges, it was pretty hard to wrap my mind around rotating the stack to keep track of variables, but when I got it right it was pretty cool.