The five capital letters are 96 years old. They’re embossed on terra cotta panels mortared into brick on the north face of the historic Bemis building in Sodo, and they’re beautiful. Almost regal.

But in 2004, federal officials said states could use another font - called Clearview - that research showed might be easier to read on dark signs that use white letters.

Shake Shack deserves some of the credit for popularizing the 70-something-year-old font. The sans serif typeface, characterized by pointy peaks and a low-slung x-height (that's the letter's ...