Picture this: you doodle a huge, realistic-looking door right on the hallway wall. The handle’s a bit too shiny, and the frame is just a line. When someone actually pulls the handle, a tiny pop‑up door slides out from the sketch, and a goofy cartoon character pops up, winks, and says something silly. It’s instant surprise, no tech needed, and everyone’s left wondering if they just walked into a comic strip.