Can you solve this pier puzzle?

I've been a fan for a couple years but just stumbled on this video.  There is a neat follow up to this that you missed!  Other commenters have pointed out the result of the "reflection" solution is that it shows the angle of incidence equals the angle of reflection where the paths hit the shoreline, just like a beam of light.  In fact, a beam of light behaves in a way that it follows the path of least time (and in this case, distance) given the constraints of the starting point, ending point, and anywhere on a line of reflection.  This can ALSO be used to solve an analogous riddle, where you have to find the path of minimum time between two cities separated by a border that is a straight line, but the two cities have different speed limits.   If you use the ratio of the two speed limits, you can use that as the index of refraction in Snell's law from optics to solve that problem easily!
In fact, this is an example of using the behavior of a physical phenomena to solve a mathematical problem.  Soap-films and Steiner trees is another example that comes to mind.
Thanks for all you do!