The man walks over, a little confused by the sign. "Did you make a mistake with the sign? It should be the other way around, or it's not a very good sale."

The merchant smiles in response and says "Nope, you saw correct. £1 each, or 3 for £5. It's been getting me a lot of customers, so it must be doing something right."

"But it's completely backwards! ...Let me try to explain another way. I'd like to buy one melon."

"That'll be one pound."

The man hands over a pound and receives his melon. "I'd like to buy a melon."

"That'll be one pound."

The man hands over a pound and receives a second melon. "I'd like to buy a melon."

"That'll be one pound."

The man hands over a pound and receives a third melon, then begins to gesture towards his purchases. "Look, do you see what I just did?"

"Yes, you purchased three melons. No refunds, by the way."