Archimedes (287-212 BC) was a brilliant mathematician who established the principles of plain and solid geometry. He is said to have invented the hydraulic screw for moving water from one level to another. He also proved that the volume of a sphere is equal to two-thirds of the volume of the smallest cylinder in which that sphere will fit. Archimedes is said to have been so proud of his work on the volume of a sphere that he asked that a figure of the sphere and cylinder be marked on his headstone. Wait! There’s more!