Impossible bottle

An impossible bottle is a type of mechanical puzzle. The term refers to any bottle containing an object that does not appear to fit through the bottle's mouth.

The ship in a bottle is a traditional type of impossible bottle. Other common objects include matchboxes, decks of cards, tennis balls, racketballs, Rubik's Cubes, padlocks, knots, and scissors. These may be placed inside the bottle using various mechanisms, including constructing an object inside the bottle from smaller parts, using a small object that expands or grows inside the bottle, or molding the glass around the object.