Moments after I completed my last Processing sketch, I wanted to explore other variations on the theme. The simplest one being drawing a shape on the canvas rather than a simple line. This couldn't be simpler! Yup, that's that. Well, how about a bit more in the way of the motion of the shape. We covered simple rotation about an axis, so let's try a different model. The Processing documentation details a number of possibilities, and one that caught my eye is sinusoidal motion. Motion on curves is a classic technique to achieve smooth animations such as easing. So let's take a look: Now, you can easily read lots of technical descriptions of this concept, some with exquisite detail. My favorite has been reading about Simple Harmonic Motion. This concept takes a fairly esoteric notion and applies it to describe interesting behaviors like uniform circular motion or the motion of a mass on a spring. In practical application, the sine function allows you to achieve a fairly smooth and organic motion without a lot of overhead (fewer lines of code, fewer minutes of thinking). I pass our increment value through this function to give me the rotation value. The result is a hypnotic, springy motion. I added a bit of spice by having the fill color pass through the same sine-based alteration. Give it a shot, and show me any other trig based transforms you've seen in the wild.