[slideways...]

why cant there be teeth? you would need to design some crazy ass cone shaped dealy-o though, with some sort of tooth design that would allow there to be progressively more teeth toward the fatter part, but also with a tooth merger design, im thinking sort of like how railroad tracks merge, sort of. otherwise unless there were some sort of huge gripping power between the cone gear and the green gear, something that could withstand more torque than a CVT. and i dont think thats realistic as far as manufacturing cost and complexity, without using teeth.