Stop Motion Animation of Falling

I shot this using my phone and the Stop Motion Studio app. I put my phone on the edge of my desk so that it overhung the floor. I planned out the arcs using Fourth Down at Half Time. For the X-axis, I measured the distance from the peak of the arc to the contact and multiplied that by 3/4 to get the halfway point. I then took the distance between that point and each of the keys and multiplied those by 3/4 to get the inbetweens. For the Y-axis, I simply spaced it out to move 2 inches every frame.