12 years ago, I made an ebike, where the motor turned the crank directly, to which the pedals were attached. That meant that the bike pedalled the rider when you twisted the throttle. It was quite interesting to ride, but I soon got used to it. I still can't figure out if it would be legal today. The power has to stop when you stop pedalling. It meets that criterion, but the only way to stop pedalling is to let go of the throttle.