https://en.wikipedia.org/wiki/Seymour_Cray

> Cray avoided publicity. There are a number of unusual tales about his life away from work, termed "Rollwagenisms", from then-CEO of Cray Research, John A. Rollwagen. Cray enjoyed skiing, windsurfing, tennis, and other sports. Another favorite pastime was digging a tunnel under his home; he attributed the secret of his success to "visits by elves" while he worked in the tunnel: "While I'm digging in the tunnel, the elves will often come to me with solutions to my problem."