They are also known as Bernal–Fowler rules, after British physicists John Desmond Bernal and Ralph H. Fowler who first described them in 1933.
[1] The rules state each oxygen is covalently bonded to two hydrogen atoms, and that the oxygen atom in each water molecule forms two hydrogen bonds with other water molecules, so that there is precisely one hydrogen between each pair of oxygen atoms.
The resulting configuration is geometrically a periodic lattice.
The distribution of bonds on this lattice is represented by a directed-graph (arrows) and can be either ordered or disordered.
A nice figure of the resulting structure can be found in Hamann.