Set number of shapes and resolution, then press the button to start. Resolution 2 is just pixel by pixel in the standard Scratch resolution. Res. 5 is dangerously high and must be done on phosphorus!
Much faster on Phosphorus: http://phosphorus.github.io/#76155152 On mobile devices: http://phosphorus.github.io/app.html?id=76155152&full-screen=true Ellipses coming soon