On the Guédelon construction site, one of the first stages of the stonemason's work is squaring, which consists of cutting the block to make a parallelepiped. A first carving cut on one of the faces of the limestone block serves as a reference for the second carving located on the opposite side of the same face. Rulers and squares make it possible to align the two carvings and to carve the faces of the block in a flat manner. In addition to the ruler and square, squaring requires the use of a pick or a polka, depending on the hardness of the stone.