0 a flat piece of metal or plastic in the shape of a triangle with one angle of 90°, used for drawing angles --
These set squares come in two usual forms, both right triangles: one with 90-45-45 degree angles, the other with 30-60-90 degree angles.
Traditional draughting techniques used 30-60 and 45 degree set squares, and that determined the angles used in these views.
Some set squares also have these curves cut in the middle.
This instrument was basically a carpenter's set square with a graduated arc and plumb-bob placed in the muzzle to measure an elevation.
Less commonly found is the adjustable set square.
Other tools used are circle compass, ruler, and set square.
The most simple form of set square is a triangular piece of transparent plastic (or formerly of polished wood) with the centre removed.
Different objects such as a book, a set square, two stepping stools and an egg float around the main figure.
