Diocles was a mathematician who lived in ancient Greece about 2,000 years ago. He is most famous for his work in geometry, which is the study of shapes and figures. Diocles wrote the book On Burning Mirrors which taught how to use mirrors to reflect the suns rays. He also wrote about finding the area of triangles and circles and described how wedges, blocks, and other shapes fit together. He even showed how to calculate the volume of a sphere, which is a round object like a ball. Diocles was a bright mathematician whose work still influences modern mathematics today.