Around the time Alexander and his students were about to leave, Billy finally solved the last mystery of the cart. To make the potency start to appear, he had to change the aerodynamics of the vehicle in a way that it would do better against the wind. Since the engine wasn't big and didn't have to be on the front of the vehicle, Billy made the front of the cart to have a triangular shape. He even put windshields in front of it. Making glass was just that easy for him now.
This might be hard to believe, but glass is made from liquid sand. More specifically, glass is made by heating ordinary sand, mostly composed of silicon dioxide, until it melts and turns into a liquid. You may wonder why the same thing doesn't happen on hot days at the beach. Still, the answer to that is quite simple: the melting temperature that the sand needs is very high, around 1700° Celsius.