How do you ensure a steady supply of drinking water to a city in the dry, arid, Mediterranean Climate? How do you get water from the spring located on the other side of a mountain to your city? If you start from both sides of the mountain, how do you ensure the two tunnels will meet? You think outside the box, of course or you ask your geometry class. Watch Polycrates solve the problem of providing the city of Samos with water in part three of this five part series.