William Walcot RE (10 March 1874 – 21 May 1943) was a Scottish architect, graphic artist and etcher, notable as a practitioner of refined Art Nouveau (Style Moderne) in Moscow, Russia (as Вильям Францевич Валькот). His trademark Lady's Head keystone ornament became the easily recognisable symbol of Russian Style Moderne. In 1920s–1930s, he concentrated on graphic art and was praised as "the best architectural draftsman" in London. Source: Wikipedia (en)