Lockpick ExtremeThe Angle of Repose
My dad was a mechanical engineer who retired early due to blindness. In his retirement he translated technical documents from German to English with the help of my mom, a tape recorder and a speech card in his XT computer. While translating a patent application for John Deere Co, he saw the claim of using the Angle of Repose to measure properties on MOVING FARM EQUIPMENT. He had to tell his Deere contact how that wouldn't work due to vibration effecting how a material piles on any surface. They abandoned that US patent claim.
Thats how and why I learned the name of this phenomenon.
https://en.wikipedia.org/wiki/Angle_of_repose
