The "magic" of this project is the nylon conductive "Maker Tape" which is like copper foil tape on steroids. It's strong, so it can hold up to the tension it's being placed under. This is tape that you can't really tear with your hands, you need scissors to cut it.
The tape is great for paper circuits, LEGO-based circuits (using LEGO baseplates as circuit boards) and works well for wearable when you don't want to sew. It's also easy to remove, which is something we can't say for copper foil tape. (We still have some of that stuff stuck to things years after abandoning it.)
One thing we discovered after building this was how much fun it was to crank the thing. I mean, we've pressed a million buttons, turned a million knobs, we've used ultrasonic and infrared sensors, and done a lot with capacitive touch, but somehow this simple turning mechanism is just... a lot of fun to crank!