Make Motion More Natural Using a Bezier Curve:

This challenge animates an element to replicate the movement of a ball being juggled. 

Prior challenges covered the linear and ease-out cubic Bezier curves, however neither depicts the juggling movement accurately. 

You need to customize a Bezier curve for this.

The animation-timing-function automatically loops at every keyframe when the animation-iteration-count is set to infinite. 

Since there is a keyframe rule set in the middle of the animation duration (at 50%), it results in two identical animation progressions at the upward and downward movement of the ball.

The following cubic Bezier curve simulates a juggling movement:

cubic-bezier(0.3, 0.4, 0.5, 1.6);

Notice that the value of y2 is larger than 1. 

Although the cubic Bezier curve is mapped on a 1 by 1 coordinate system, and it can only accept x values from 0 to 1, the y value can be set to numbers larger than one. 

This results in a bouncing movement that is ideal for simulating the juggling ball.