What Goes Down Must Come Up

In an alternate world, everything that goes up must come down. Here, you can see that two red balls fall down: one on the ramp and one that gets pushed down, and two red balls go up: the ball on the seesaw and the ball on the right. 

Gravity in this alternative world works differently: the sky is the floor and the ground is the sky. The large red ball being launched into the sky from our point of view is merely just falling from the sky in theirs. This machine would be a thing of wonder due to the balls "rising" to the sky against gravity.