The rough copy of the layout is made with a specific CAD program, but every millimeter is reviewed and rehearsed manually, correcting every distance between the conductive traces to bring to zero any capacitative or inductive defect in the future board. Every corner of the conductive traces is eliminated keeping into account the physical effect of the dispersion of the angles. In balanced circuits, like that of the DuePre, we look for an almost perfect specularity of the (piste) on which the two portions of the signal travel. Generally we seek the best compromise between a right distance of the components and the shortest possible course between input and output.