I ran across a rainbow of printing errors, courtesy of Topps.
These 1989 Rookies cards came with a little bonus streak of colored foil. Steve Wilson has a green strip across his chest.
Gregg Olson has a blue strip across his name.
This is what the Gregg Olson is supposed to look like. See, no foil strip anywhere. I don't know how those could have gotten on the cards accidentally.
Last, but not least is Mr. Bob Milacki. He has a pinkish/purple/red strip across his name. I know printing errors are fairly common, but these cards aren't supposed to have any foil on them so I don't understand how this one happened.