Millstones are used for grinding wheat and other grains. Initially people used a rubbing stone to grind the wheat manually on a simple flat grinding
stone. Later they grinded the grain into flour with the help of millstones. The two superimposes grinding stones could be turned by hands. Because of the force
of the stones on the grain, it deforms and finally breaks. Millstones work together in pairs. You have a bottom stone or “bed stone” and a “runner stone”.
The latter is the upper turning millstone. Millstones have a furrow pattern. Are the furrows used to transport the grain between each pair of
crossing furrows? That way, the furrows of both stones would work like a pair of scissors.