The ship in a bottle is a traditional type of impossible bottle. Other common objects used include matchboxes, decks of cards, tennis balls, racketballs, Rubik's cubes, padlocks, knots and scissors.
In nearly every impossible bottle, the object inside has been carefully disassembled and reassembled inside the bottle. For example, to get a deck of cards inside a bottle, the empty box is first rolled up and inserted, followed by each card one at a time. Using some long forceps and other tools, everything can be put back together again and the result is something that looks impossible to one who does not know the secret. Also, objects may be inserted into a bottle whose neck is initially wide enough to accommodate them, and then with glass-blowing techniques the neck is made smaller than the objects.