Beall-Dawson House in Rockville, Maryland is an 1815 Federal-style home built for Upton Beall, then Clerk of the Circuit Court. It has been owned since 1960 by the Montgomery County Historical Society. Almost 200 years of use has left its mark. Below is the wooden threshold leading into the home's main parlor. The threshold shows the pattern we have seen often, the most wear in the middle where the frequency of use is greatest, trailing off to lesser usage and wear at the edges. A bell- (Beall?)-shaped distribution of wear.