Old project. Please see my newer one: https://scratch.mit.edu/projects/54631830/ A quick test for my RPN tool for drawing a quadratic Bézier curve. Click and drag the nodes to change the shape of the curve. The resolution of the curve can be changed by changing the "res" variable. A higher resolution will result in a smoother curve, but it will take longer to redraw. Fullscreen and turbo mode (shift click the green flag) for best results!
Bézier curves on Wikipedia: http://en.wikipedia.org/wiki/B%C3%A9zier_curve