Drag the sliders and use the left and right arrow keys to rotate the ellipse. Press p to bring the circle to your mouse, and press r to bring the rotation point to your mouse. The green cross is the centre point of the ellipse, and the blue cross is the rotation point. The faint ellipse in the background is what the ellipse would look like if the rotation point was the same as the centre point. Start won't do anything unless length is less than 360. Also, the x and y position may seem a bit odd if the rotation point isn't the same as the position of the ellipse.
