Leonardo da Vinci's Treadmill Powered Crossbow Keychain

Treadmill Powered Crossbow (c. 1480) by artist Leonardo da Vinci (1452-1519). This war machine drawing is a vintage Renaissance Era fine art military painting. A large treadmill with a man walking on it powering several cross bows. A great design for science geeks. Sketch from one of Leonardo da Vinci's many journals. Leonardo kept a series of journals in which he wrote almost daily, as well as separate notes and sheets of observations, comments and plans which were left to various pupils and were later bound. Many of the journals have survived to illustrate Leonardo's studies, discoveries and inventions. Most of the journals were written backwards in mirror script. His journals were later published, 165 years after his death.