Uses hermite vectors to build a spline which is then traced by a rainbow. Spline points and control points can be moved using the mouse. Also, particles fall from the top of the screen and are erased after touching the spline, showing how to do collision with a spline.
Use the mouse to look around and click to throw a ball. Ball is launched from the camera based on where it is looking. Look straight up, ball goes straight up and drops straight back down.