Square (tool)

Squares see common use in woodworking, metalworking, construction and technical drawing.

[1] Some squares incorporate a scale for measuring distances (a ruler) or for calculating angles.

A bright light or feeler gauges can be used to check for gaps between the square and the object being referenced.

[35] Historically squares have also been used by woodworkers, such as joiners and carpenters, as symbols in signs and heraldry to represent their trade.

[36] The square as a symbol is also seen in artistic representations of the Christian saints Thomas the Apostle and James the Less.

Ancient Egyptian wooden try square from the 20th century BC.
Checking a try square for accuracy against itself.
The square and compass symbol used by Freemasons .
Statue in Helsinki of Thomas the Apostle holding a square.