It wasn't clear, but I believe that shifting gears would be accomplished by moving the pulley that's attached to the triangular frame on the pedals along the ax

It wasn't clear, but I believe that shifting gears would be accomplished by moving the pulley that's attached to the triangular frame on the pedals along the axis of pedal rotation. Move it closer to the pedals, and you downshift. This could be done continuously, rather than having discrete gears.