DANIEL BURNHAM. The Railway Exchange. An Original

Terra Cotta had the benefit of being a factory produced material.  And the Railway Exchange is covered with it.  Still there was flexibility for special conditions.  Like this one at the mainstair.  A border of 26 layers (depending on whose counting)  transitioning from arc to angle. DID I SAY TWENTY-SIX LAYERS.....???   

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I can't help but notice that islamic geometry at the return air grill. I first saw this in John Root's work and the Rookery. But it is pervasive in early Chicago School architecture.

One more story to uncover.