Honeycomb

The "sagacity of the bees" - in choosing tesselating hexagonal prisms as their storage architecture - has been known for thousands of years.

Pappus - writing some sixteen hundred years ago - wrote:

"the hexagon is greater than the square and the triangle and will hold more honey for the same expenditure of material used in constructing the different figures".

However, the question of whether a tesselating pattern of hexagons was indeed the optimal way of covering the plane with a fixed tile of a given area, while minimising the length of the edges was only resolved recently - in June 1999 - when Thomas C. Hales found a proof [available here] of what had come to be known as the honeycomb conjecture.