For class credit, Marco Facciola, 16, built a fully functional bicycle out of wood. No metal was used. He was even able to create the chain and ratcheting system (to allow coasting) out of wood and glue.

Facciola was inspired to create a wooden bike after his grandfather had to make wooden wheels for his bicycle during World War II in Holland when rubber was scarce.

You can read the details of how he built the bike here.

I bet it rides horribly, though.

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Via: Neatorama