First, write the six parts of the triangle (three vertex angles, three arc angles for the sides) in the order they occur around any circuit of the triangle: for the triangle shown above left, going clockwise starting with a gives "aCbAcB". Next replace the parts that are not adjacent to C (that is "A, c, B") by their complements and then delete the angle C from the list. The remaining parts can then be drawn as five ordered, equal slices of a pentagram, or circle, as shown in the above figure (right). For any choice of three contiguous parts, one (the "middle" part) will be adjacent to two parts and opposite the other two parts. The ten Napier's Rules are given by