The design, made between the years 1487 and 1505, represents a study by Leonardo for the construction of a clock. Leonardo Da Vinci imagined a rotating device at the end of which a chain was attached with a weight. The chain and the weight, rotating, wrapped around and unfolded around two metal pins giving the clock a cadence. Choosing a selection results in a full page refresh. Press the space key then arrow keys to make a selection. Use left/right arrows to navigate the slideshow or swipe left/right if using a mobile device