Whoever built the Octagon might have constructed it especially for this
sort of crisis. Its walls had grooves at regular intervals which were
just right for the hands and feet, and it wasn't very long before I was
parked up on the roof beside the Right Hon., gazing down at one of the
largest and shortest-tempered swans I had ever seen. It was standing
below, stretching up a neck like a hose pipe, just where a bit of
brick, judiciously bunged, would catch it amidships.