* The degrees of the angle included between each arm is twice the angle number. For example, at the 45° number the included angle is 2 * 45 = 90°... a right angle. Same at the 135° number. 2 * 135 = 270°, where 360 - 270 = 90°. Altenatively, use negative angles. 135 - 180 = -45°. Then, 2 *...