Flag to restart. Click switch on to find equidistances* Drag diamond or gold strip to see parabola change. * "Find equidistances" also tells each blue dot to find a point equidistant from diamond and gold. "Show tangents" of parabola also shows perpendicular to tangents. The perpendiculars go from the y of each point on the directrix (gold) to the focal point (diamond).
As if attracted equally to diamond and gold, each blue dot goes to spot equally distant from the two. The best feature here is that you can drag the diamond and gold to get a new parabola in realtime. Gold line is "directrix" and diamond is the "focus" with parabola as set of points equally distant from directrix and focus. Uses minimal code.
