At 38:35 we see the crossword clue for 11 down: "Running over a mound is an effort." 9 letters. "endeavour" is an anagram of "over a dune" but what does "running" have to do with it? The only idea I have is that the phrase "Running over a dune" can be used as a noun. "Running over a dune is an effort" is a complete sentence while one would have to use italics to write something like "over a dune is a form of effort"