Many things can create one, ...
Many things can create one, it can be of any shape or size, it is created for various reasons, and it can shrink or grow with time. What is it?
Bored on the train
Three men and a young woman are travelling on a train. The four passengers get talking and the chat soon takes an erotic turn.
The young woman proposes: “If each of you give me $1 I will show you my legs”. The men, charmed by the woman, all pull a dollar out of their wallet and she proceeds to pull up her dress a bit to show her legs.
The woman then says: “If each of you gentlemen give me $10 I will show you my thighs”. Again the men pull out their wallets, hand over the money the money and the woman pulls up her dress to show her legs.
The woman continues: “If you give me $100 I will show you where I was operated on for appendicitis”. All three hand over the money.
The woman then turns to the window and points outside at a building they’re passing. “See there in the distance, that’s the hospital where I had it done!”
Original joke found on https://boards.fool.com posted on July 5th 2000, posted by gwgross, versions with more details could be found a bit later