Spiral staircase - 'crescent' motif modulus 3

Spiral staircase - 'crescent' motif modulus 3

This muqarnas spiral staircase uses the 'crescent' motif. By inspection one can determine that the sections are from the modulus 3 'crescent' motif expanded dome, that is from the third layer.

The 'crescent' motif method of dome expansion is described here:

http://www.ensightful.com/content/crescent-motif-dome-expansion

There are an indeterminate number of distinct spiral staircase muqarnas designs possible.