night vision boot
Down the street from my shop at the time was a fledgeling thermoform business. Its enthusiastic young founder was for ever chasing up interesting work. In this instance engineers were seeking a solution to ice build up on the night vision turret mounted at the nose of attack helicopters. I turned this pattern down over which thin Teflon was thermoformed. The idea being that ice would be unable to remain for long on the Teflon surface.
I don't think this program went very far but I enjoyed the challenge of creating such a large - and yet accurate - turning.