We're Leah and Tasha and we tackled this riddle by investigating how to make a square wheel "roll." We began by making some toy-sized square wheels and used them to study why a square wheel does or doesn't "roll." We found that once the wheel is up on its corner, it "rolls" forward until it rests on its side. We also noticed that to get the wheel back on its corner the bike has to actually rise up in the air. We were standing near some steps when we found that the right size square can "roll" up stairs quite smoothly. So we wondered if this was a clue? How would you make a square-wheeled bike "roll" smoothly?