No tricks. Just physicsΒ
Let's drop the ball (without initial velocity) on the floor from the height H.
It will bounce off the floor to a height h1 < H.
Let's drop another ball ...
It will bounce off the floor to a height h2 < H.
 05 - b2.mp4
05 - b2.mp4 03 - b1.mp4
03 - b1.mp4Now, what if you put the ball on the ball and drop them both (without initial velocity) on the floor from the height H ?
Let's take a look...
 01 - 2-balls-0.mp4
01 - 2-balls-0.mp4 02 - two-b.mp4
02 - two-b.mp4 04 - two-b-2.mp4
04 - two-b-2.mp4How can the ball bounce higher than the height from which it was dropped without initial velocity?