99% Invisible producer emeritus Avery Trufelman traveled from New York to San Francisco recently, and took host Roman Mars to see an unusually shaped old building on the west side of the Bay. As it turns out, this peculiar octagonal home isn't unique -- there was a whole architectural fad of building these back in the mid 1800s, tapping into a parallel trend: self-improvement.Publisher Orson Fowler (most famous for being a phrenologist) used his professional position to self-publish a book about the many benefits, health and otherwise, of living in an octagonal home. His book, Octagon House: A Home For All, became a sensation. In its wake, hundreds of octagon houses started popping up all over the country.The Octagon House