IDK how much of it* is patented.. hub motor, out of a wheel, driving the left side of a tandem crossover crank,
allows the rest of a mountain bike drivetrain to be used to apply the power..
but, to make room for the motor, the bike needs to be a longtail, like an Xtracycle, or a Big Dummy,
or built from scratch.. , for the purpose..
* Aka 'stoke monkey'..