Final answer:
The rafter angle square, often called a speed square or magic square, is a versatile tool composed of a protractor, try square, and framing square used in carpentry and woodworking.
Step-by-step explanation:
The instrument being described is known as the rafter angle square, commonly referred to as a speed square or magic square. This versatile tool is a staple in carpentry and woodworking, combining several functions into one compact design. Unlike the quadrat square used in ecology to determine population size and density, which is the square made of various materials for static organisms, the rafter angle square is used in construction and fabrication tasks.
The rafter angle square serves multiple purposes. It can be used as a protractor for measuring and laying out angles, a try square for marking square cuts on timber, and as a framing square for determining the correct angles for roof rafters, stair stringers, and many other frameworks. Its durability and ease of use make it an essential tool for carpenters and DIY enthusiasts alike.