This is a simple Bézier Curve renderer.
Drag the white dots to modify the curve. Push "Add" to add another dot, and push "Delete" to remove one.
Change the "resolution" slider to change how well the curve is drawn.
This renderer renders by drawing a certain number of segments.
In the future, if I can optimize this, I may also try to make a curve filler. A curve-filler could be used for drawing real fonts in Scratch - but it would have to be very highly optimized to be useful.
Read about Bézier Curves: https://en.wikipedia.org/wiki/B%C3%A9zier_curve
10/2/16: Original project shared
10/2/16: Make it possible to draw with any number of control points
10/4/16: Restrict movement of control points; change rendering method from recursive to segmented
10/4/16: Use caching for binomial coefficients rather than recalculating them every segment