/**
* Draw a filled equilateral triangle of radius r, centred at <location>.
*
* @param location the Point at the centre of the triangle
* @param r radius is the length from the centre of the triangle to any of its corners.
* @throws RuntimeException if r is negative
*/
public static void filledTriangle(double x, double y, double r) {
offscreen.fill(ShapeAssist.triangle(x, y, r));
draw();
}
