Originally Posted by prathmann

Hardly. I've never seen any airport runways constructed out of treadmills, but I've seen a number of cyclists using oval chain rings and tried them myself at one time. And they've been around for many decades. My test ride was back in the '70s and it was a very old idea at that time.
BTW, the rear derailleur cage moves very slightly back and forth as the cranks turn but it's almost insignificant. OTOH, the change in effective gear ratio is quite pronounced. As I've suggested before, try it yourself - the oval chain rings are not hard to find.