When I was a child, I watched the 1960's Batman TV series every chance I got. One of the episodes came to mind this morning when I was trying to explain why the Secret Sisters gift exchange was a scam. Someone is trying to scam the town by proposing a pyramid scam (invest a little money now, multiple people pay you down the line as they invest) and he mathematically proved that the only people it would profit were the people who started it.
The only concrete image I have in my head is Batman (Adam West) standing in front of a room of people and using a pointer on a piece of poster board on an easel with an image of the pyramid and showing the math that every new person would need to bring in a ludicrously large number of other people in for the scheme to work.
Which episode was that?