John Tayloe III of Mount Airy, Virginia, asked Benjamin Henry Latrobe and William Thornton to compete for the design of his townhouse in 1800. Tayloe owned a lot at the NE corner of the intersection of New York Avenue and 18th Street, a few blocks from where the White House was being built. Tayloe chose Thornton's design, the house was built, and it came to be known as the Octagon. Many people are puzzled by its name, expecting all octagons to be "regular" octagons. Very simply, the house has eight sides, one side being curved.
In 1998, I co-curated at show of perspective drawings at the Octagon Museum, and was commissioned by the Museum to recreate Latrobe's design for Tayloe's house based on his working drawings now at the Library of Congress. My final drawing is below. I drew it using perspective techniques dating to the Renaissance and using simple tools: a scale, a pencil and a straight edge. Click to enlarge.