Now, for the first time, production studio Above Average can reveal the lives of the secretive.
"We make sound," David tells us. "We think of it as an artform," his companion, Julia, adds. "Their ceiling ... is our stage. And we're dancing across it."
David also revealed that the illusion of constant activity is carefully constructed with elaborate shift patterns.
"A floor is but a movie screen, to project the mind's eye," David said, before bouncing three basketballs concurrently.
"Some people might say what we do is passive aggressive - thank you!" he added.