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The haunted vending machine

This JAVA applet is a software implementation of the Vending Machine puzzle, a mechanical puzzle by Oskar van Deventer, see photo below. The object is to insert the indicated amount of coins. However, the machine seems haunted and keeps rejecting your coins. Can you persuade the machine to accept your coins?

Here on the right is a photo (circa 2002) of the original mechanical Vending Machine puzzle, designed and hand-crafted by Oskar.

Update June 2022: And 20 years on... here is a video of the next generation of the same puzzle, 3D printed and demonstrated by Oskar himself.

concept & puzzle designs - © Oskar van Deventer - 2002
puzzlescript implementation - © Andrea Gilbert - 2022
The haunted vending machine was inspired by the MB game Avalanche