Zebra stripe light dent removal aid - GIF

[Frank S]

"Zebra stripe" dent?
Phrase "Oil can" dent too old fashioned?

No they are referring to the light emitter causing the stripes the dent reflects the light at different angles from the normal body shape. In paintless dent removal these stripes aid the body man to see where he should massage the metal with a poly tipped hammer while adding gentle pressure with a ninja stick from behind.
When cars were made out of 18 ga metal this would not have worked