Manuscripts/Mixed Material Article by Alexander Graham Bell, October 11, 1910
Four of these unit cells, connected together at their corners, form a four-celled structure, having itself the form of a tetrahedron containing in the middle an empty space of octahedral form, equal in volume to the four tetrahedral cells themselves. In my paper, I showed that four of these four-celled structures connected at their corners resulted in a sixteen-celled structures of tetrahedral form, containing, in addition to the octahedral spaces between the unit cells, a large central space equivalent in volume to four of the four-celled structures.
In a similar manner four of the sixteen-celled structures connected together at their corners from a sixty-four-celled structure: Four of the sixty-four-celled structures form a two hundred and fifty-six-celled structure, etc., etc.; and in each of these cases an empty space exists in the center, equivalent to half of the cubical contents of the whole structure, in addition to spaces between the individual cells, and minor groups of cells.
Kites so formed, exhibit remarkable stability in the air under varying conditions of wind, and I stated in my paper that the kites which had the largest central spaces seemed to be the most stable in the air. Of course these were the structures that were composed of the largest number of unit