A set square is a triangular tool used in technical drawing and drafting. It typically has two right angles and is made from materials like plastic or wood. Set squares help create precise angles, usually 90 degrees and 45 degrees, making them essential for architects and engineers when sketching plans. Set squares are often used in conjunction with a ruler or straightedge to draw straight lines and accurate angles. They are commonly found in classrooms and design studios, aiding students and professionals alike in producing clear and accurate representations of their ideas.