The original note, as written at the time
A set of urban-architectural schemes demonstrating the concept of colossal pyramidal structures that form the basic structures of cities. Some pyramids are ideal with flat sides; some have sides bent in or bent out.
Ongoing development
A set of urban-architectural schemes built on colossal pyramidal structures as the basic structures of cities — some ideal with flat sides, some with sides bent in, some bent out.
The pyramid is not a shape here, it is an argument about how a city holds itself up. A pyramid is the only large form that is entirely structure and entirely ground: it needs no frame, no transfer beams, no special foundation. Every part of it is doing work, and the work reduces as it rises.
That matters because it produces a city with a completely different economics of space. The lower levels are the most expensive to build and the least useful for daylight; the upper levels are cheap and bright. Invert the usual arrangement and put the cheap public uses low and the quiet ones high, and the building starts to allocate itself.
Bending the sides is the refinement that stops it being a monument. Bent in, the form tightens and produces courtyards and shadow. Bent out, it produces terraces and catches sun and wind. The flat-sided version is the diagram; the bent versions are where the architecture begins.
The honest objection is that a pyramid is a terrible plan for a city, because the deep interior has no daylight and no natural ventilation, and in our climate that is not a small fault. Any real scheme has to be a pyramid with a hollow core, which is no longer a pyramid but is the only version that can be lived in.
That is the useful outcome of the sketch. It is not a proposal for a building. It is a way of asking how much of a city can be structural before it becomes a problem.