About
Drawing parabolic line designs is easy: connect three or more points with straight lines, then interpolate between those to form the rough outline of a parabola.
Lots of us made them in elementary school using a pencil, ruler, and graph paper. This nostalgia must be what's reminded me of them over the years, reworking a simple interactive demo each time.
Since touch screens are a given on new phones, it was time to rewrite the old Flash version (itself reworked from an earlier Java applet) using JavaScript and Canvas, and add support for mobile. It was also a good opportunity to allow points to be dragged around, and add a snappy grid for more precise designs.
That said, drawing parabolic line designs the old-school way still does the job!