Click and drag to draw the slide. Press space when ready. The longer the slide, the laggier it is. This now has physics applied, so the steepness will affect how fast the face goes. When it reaches either end, it will fly-off. And yes, the face can go backwards. :D
Yes, the color is a bit glitchy till you press space. I like it that way. However, if you want to change it so it is always changing color, by all means, do so! Yeah, it's laggy.