A "📐" is a triangular-shaped tool commonly known as a T-square. It is used in drafting and technical drawing to create straight lines and right angles with precision. The T-square consists of a long, horizontal ruler or blade and a shorter, perpendicular handle that slides along the ruler. This design allows for accurate measurements and helps in maintaining straight lines while drawing or drafting. The T-square is an essential tool for architects, engineers, and artists who require precise and straight lines in their work.