“… a building is made up of solids and voids which are geometrically related to state this relationship it is first of all necessary to visualize space as divided along three planes, mutually at right angles, into a number of cubical… cells. One series of planes is horizontal the two other series are vertical, at right angles to one another. This visualization of a space divided in all directions becomes an “armature of planes,” or foundation of three dimensional relationships. It should be thought of not as a grid or frame of three intersecting sets of lines but as almost invisible “lines of cleavage,” the whole being like a glass cube made up of smaller glass cubes.”
Sir Edwin Lutyens
An Armature of Planes