Is anyone familiar with these types of markings. I just started coin hunting and one thing I've found for sure is people do some weird things to coins, especially to pennies.
I assume you mean the circular damage from a rotary grinder ?? versus the horizontal damage from scraps and scratches ?
In the "artsy" world it's not "why would someone do this to a coin" but "why not" and how many times does one damage coins to get one the way they want it to look.