[nervous_jessica]

Nice! I haven't seen these before. There's also a brand of puzzles called Schmuzzles that are based on an escher lizard and tile. I would say the difference between these and our torus-based puzzles is that they employ a tessellation cut with repetitive piece shapes such that the image is guiding the construction (as all pieces fit in all places). In our puzzles, each piece only goes one place as they each have a unique shape. Our Klein Bottle and Cross-cap puzzles is are a new idea (to the best of my knowledge).