2+√3
This window, in Champions Hall at the University of Arkansas, illustrates a particular twelve-fold tiling substitution scheme: each individual tine may be refined into an arc of smaller tines, and itself sits within a larger arc of tines, within a larger arc, etc, etc ad infinitum.
This sort of structure could, hypothetically, form the basis for encoding computation within the hierarchical structure: the tines can individually be reversed or not, each holding a bit of information.
The technicians who printed the job did great work — they chose the translucency of the lightning like zags and wiggles.
