For clarity, fig. 2 shows three separate drawings. 1 and line IK is drawn. Draw lines IJ of length GI, and KL of length KH at right angles to IK and to the same side. The line through N and shadow point B is now parallel to the equinox line of our sundial.
P is the substyle of the dial.
4 some data from fig. Point R is the intersection of line NB and the substyle. The line through V and parallel to NB is our definitive equinox line. Triangle UTP is the style triangle , which will be turned upright around the substyle, so that UT will be the pole style of our sundial. 5, the construction of the sundial is finished using conventional techniques.