Jack-in-the-Box

This is a variation on the pendulum expression.

Keyframes were applied to Jack's position at frames 0 and 1 to move him out of the box. Then this expression was applied to the position property to give him the bouncy motion:

veloc=35; 
amplitude=30; 
decay=1.0; 
y=amplitude*Math.cos(veloc*time)/Math.exp(decay*time);
position+[0,y]

Adjust the velocity, amplitude and decay parameters as needed.

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