Benjamen Walker tackles architectural forensics on this week’s Theory of Everything. The show begins with the story of Boston’s Kenmore Square as it existed before the big box hotel was installed. Having landed here in 1992 I can remember bits and pieces of it. Yep, I managed to log a few late night hours at the Rat. I remember Charlie’s, or was it Charley’s?, the corner diner that later converted to an IHOP. I remember a closed-down Narcissus. And what about Mixed Nuts, the two-man street band. They used to perform, tip jars out front, on the broad sidewalk as the BoSox fans made their way in and out of Fenway Park. Their instruments? Air guitars.