Self-Solvable Puzzle

"This is a self-solvable puzzle. But if it doesn't solve itself within 6 months, you can return it." the old man said and handed her the puzzle. "But what's fun about a puzzle that solves itself?" she asked and opened the paper bag and slid it into it. "People are getting increasingly lazy while still wanting to feel accomplished, so I'm selling a lot of these at the moment. You're lucky. You got the last one. I'm waiting for another order." he said and smiled at her. "I still don't really understand it. I'd wanna figure it out myself." she said. "Then why are you buying it then, if I may ask?" the man asked. "Oh, I'm buying it for a friend." she answered. "I'm sure you are" he said and winked at her.