The blue circle should be drawn as last element, using a loop. You just need to calculate the postion of the center. Quite easy if you use polar coordinates, since an ellipse equation is simply
x = a sin Alpha + xoffset
y = b cos Alpha + yoffset
where a and b are the semi-axis of the ellipse.
I have modified your vi accordingly. There is still some tunning to be done on the x and y offset, since the ellipse is not centered on the central circle.
Chilly Charly (aka CC)
