Abstract: A layout tool for scribing an arc includes an arm, a variable location pivot point arrangement on the arm, and a plurality of mark openings spaced from the pivot point arrangement. A position fixing member, such as a nail, is engaged with the pivot point arrangement to fix the position of the tool on a workpiece at a pivot point defined by the position fixing member. A marking instrument is engaged within one of the mark openings, and the tool is pivoted on the workpiece about the pivot point to make an arcuate mark on the workpiece at a radius defined by the location of the position fixing member relative to the mark opening within which the marking instrument is engaged. The tool may be a square, which is configured with two arms that extend away from each other at a predetermined angle.