Re: [math-fun] L versus 2L

This whole sequence of comments reminded me of a true incident from approx. 1969 when a group of MIT oarsmen were in a rowing shell & a huge ship wake was headed towards it. The coach yelled & told the oarsmen to steer the rowing shell until it was "parallel to the wave". Being engineers/scientists from MIT who had taken 8.01, this (of course!) meant "parallel to the wave vector", whereupon the wave broke over the shell, lifting up both ends, and broke the very expensive shell into two pieces. The coach, of course, meant "parallel to the wave crest" -- i.e., perpendicular to the wave vector.