Canvas Demo, Experiment Six

My math is off. See that blue line? It's supposed to intersect the red line at the same place where the red line intersects the circle, and it is always supposed to be parallel to the orange line.

Sadly, my first attempt that this, I chose an angle that was exactly right for the blue and orange lines to be parallel. I was thrilled. I thought I had nailed the math on the first try. Obviously, when I animated it, I learned, apparently not. Ah, well, back to the scratch paper.