SO, can you explain how to use the two buttons that appear at the bottom of the screen?

For those who did not see it yet, this is referring to https://itunes.apple.com/app/archives/id1145966102?ls=1&mt=8. Get it now!

The left button activates and disables the zooming effect. It looks cooler with zooming, but if you want to see clearer shapes, disable it.

The right button lets you tune the effect. The exact meaning of this is unclear, but if you play a pure tone at the note it is tuned to, the result will be a circle. Other tones will be various kinds of ovals. The exact effect of this, you will have to experiment to figure out.