Trafalgar Square of Trafalgar. Surrounding the square are the National Gallery on the north side and St Martin-in-the-Fields Church to the east. Also on the east is South Africa House, and facing it across the square is Canada House. To the south west is The Mall, which leads towards Buckingham Palace via Admiralty Arch, while Whitehall is to the south and the Strand to the east. Charing Cross Road passes between the National Gallery and the church. London Underground's Charing Cross station on the Northern and Bakerloo lines has an exit in the square. The lines had separate stations, of which the
Set square for "geometry triangle"), it was originally developed and trademarked by the German-Austrian manufacturer "Aristo-Instrumente Dennert KG" (now "GEOtec Zeichen- und Kunststofftechnik GmbH") in 1964. Set square A set square or triangle (American English) is an object used in engineering and technical drawing, with the aim of providing a straightedge at a right angle or other particular planar angle to a baseline. The simplest form of set square is a triangular piece of transparent plastic (or formerly of polished wood) with the centre removed. More commonly the set square bears the markings of a ruler and a half circle protractor. The