These were in the local Buster Brown shoe store when I was a kid.

When we went into town, if the trip took us past the store, we kids all had to go in and look at our toes. Did it so many times, it's a wonder I still have toes.

Actually from what I've read and heard, it was the salesmen who got the worst of it. Evidently the sheilding wasn't that good at the back of the machine where they stood.