Draws an ellipse (oval) to the screen. By default, the first two parameters set the location of the center of the ellipse, and the third and fourth parameters set the shape's width and height. Parameters: x: (number) x-coordinate of the center of ellipse. y: (number) y-coordinate of the center of ellipse. w: (number) width of the ellipse. h: (number) height of the ellipse. (Optional)
