Hexagonal grids are unique for an interesting series of reasons:
Hexagons don't tile the plane by simple repetition of parallel lines (as squares and triangles).
Hexagons tile a plane using the smallest perimeter per number of cells: it means that every interface between cells is reduced.
The triangles in a triangular grid are a simple subdivision of a hexagonal grid.
It comes as no surprise that nature is filled with hexagons: from beehives to planets, from foam to cells: the hexagon minimizes the energy required for things to stay close to each other. Read more