On the far west of the Mainland island of Shetland, one can find remains of several watermills that date to sometimes around 1850s. The mill buildings were located one after another downstream and used the power of water to enter the mill and turn a giant paddle wheel horizontally (hence the name). The wheel turns the giant metal rod that in turns pushes two millstones, roughly 1m in diameter. Barley and oats were milled this way and the mills were common all around the self-sufficient Shetland Islands.
Shetland: Shetland Landscapes