Grocers stacking oranges demonstrate intuitive grasp of sphere-packing math

They may not know it, but grocers face some of the most difficult questions in mathematics when stacking produce each day.

Four centuries ago, the astronomer and mathematician Johannes Kepler guessed that the standard grocers’ method of piling oranges packs the most fruit into the least space. Confirming he was right had to wait until 1998, when mathematician Thomas Hales of the University of Pittsburgh, working with his student Samuel Ferguson, proved Kepler’s conjecture with the aid of 180,000 lines of computer code.