Some really fun Bullard Plots showing some cool harmonics.

A Pulse Width Modulation plot showing the pulse width going from 99% to 1% in just a few steps.

An animation that shows how a 4% distortion placed at various places from the peak to the zero crossing causes very different harmonics.

An animation showing a notch distortion at the peak of a wave showing that Even (red) harmonics are dependent on assymetry. In fact, Even harmonics only show how asymmetrical the distortion is, they don't prove anything else!