Fig. 6. Construction of a square on the base line in Figure 1 using compass and straightedge: (a) mark off distance of base line along upper extension of the perpendicular; (b) measure from either end of base line to same point on perpendicular to obtain proportion of diagonal of the half square; (c) draw circle of same radius from intersection of base line and perpendicular; (d) use points of intersection on two original circles to complete square with straightedge (drawing: Center for the Study of Architecture). return to text