Maxwell von Stein's bicycle invention uses a flywheel to store energy. Instead of braking, he can slow the bicycle by transferring the kinetic energy from back wheel into the flywheel -- which spins between the bars of the frame. Then Max can send the flywheel energy back to the wheel when he wants a boost. Watch the video. Thank you, Rasmus.
Related: Job Ebenezer's Dual Purpose Bicycle, mentioned in the article on pedal powered machines.
