Abstract: A tool is provided for laying out precise angles in construction of structures such as a foundation. The tool includes three corners including a first corner, a second corner and a third corner. Each of the corners are spaced from each other by separate strands including a first strand, a second strand and a third strand. Each of the strands are inelastic so that when fully extended they have a precise length. The lengths of the three strands are precisely provided so that the tool is provided in the form of a triangle with angular measurements of each of the corners precisely as desired. Preferably, one of the corners measures exactly 90° to facilitate the forming of a structure with a foundation having corners which measure precisely 90°.