Nothing but a coincidence, based on an artifact of the measurement system used by the culture to build the structures in question.

Quote

Coincidence is the noteworthy alignment of two or more events or circumstances without obvious causal connection. The word is derived from the Latin co- ("in," "with," "together") and incidere ("to fall on").

... A coincidence does not prove a relationship, but related events may be expected to have a higher index of coincidence. From a statistical perspective, coincidences are inevitable and often less remarkable than they may appear intuitively. The odds that two people share a birthday, for example, reaches 50% with a group of just 22[1] (see the Birthday paradox).
(emphasis added) [en.wikipedia.org]

There is no causal connection in the evidenciary record to suggest a master plan including the pyramids of Khufu, Khafre and Menkaure, except that the later ones were built with the knowledge of the earlier ones' existence. These Giza-based coincidences require, as a bare minimum, that we ignore Djedefre and Kaba... two kings who built pyramids away from Giza during the Fourth Dynasty, and chronologically interjected between Khufu, Khafre and Menkaure. A master plan that was twice abandoned is hardly a well-defined plan.

All in all, this Spirograph exercise contributes nothing to our knowledge of the Old Kingdom. It does, however, tell us a lot about modern technology and autocad programs.

Anthony

You can lead a horse to water but you can't make him think.