Zebra light fixture for finding car body dents - GIF

[BuffaloJohn]

Very interesting - using a reflected "defraction" like pattern to highlight the errors in the door...

[metric_taper]

This probably only works with mirror surfaces. I'm thinking autobody restoration where the crusty paint and rust must be removed for proper patch repair.
I watch this guys channel;

He did wash the 1935 before doing the work. But he has an odd channel with him working on this era of pre-WWII automobiles, I think Buick, Chevy mostly. They all look like they were parked since the mid 1950s, and left in the tree row to rot.