I really like Alex's simple and neat solution.
And I actually feel bad for stealing the win from it.
I think he deserves the moral victory.
"Flicker" might be cheaper, but it's almost a fluke. The idea is OK, but the execution requires such a combination of impossible timing it should not have happened.
Try adjusting either of the two cantilever tips, or the solid plate nudger near the grey dillo, just a tiny bit, and see what a total fail it becomes!
Also:
Smith, where Jones had had "had", had had "had had". "Had had" had had the higher mark.
(Someone explaining why Smith got a higher mark for writing "had had" when Jones had written "had").
Is English the worst language ever?