Discrete geometry or combinatorial geometry may be loosely defined as study of geometrical objects and properties that are discrete or combinatorial, either by their nature or by their representation; the study that does not essentially rely on the notion of continuity.
Kepler's conjecture (Johannes Kepler, 1611): The densest way to pack identical spheres in a given space is the "canonball" arrangement, i.e., in flat layers, with each sphere resting upon three toucning spheres benath it.
