code: public void ellipse(float x1, float y1, float x2, float y2) {
          arc(x1, y1, x2, y2, 0f, 360f);
      }
docs: Draws an ellipse inscribed within the rectangle x1,y1,x2,y2.
  
  @param x1 a corner of the enclosing rectangle
  @param y1 a corner of the enclosing rectangle
  @param x2 a corner of the enclosing rectangle
  @param y2 a corner of the enclosing rectangle