This is a combination of many elementary correspondences. The number of lines [math]o[/math] and points [math]O[/math] can be any amount, in this example we chose three. In the book, we use a sequence of lines and points occurring alternately: [math]o,O,o_1, O_1, o_2,...,O_{n-1}, o_n, O_n[/math]. We allow the sequence to begin with a point (omitting [math]o[/math]) or to end with a line (omitting [math]O_n[/math]) but we insist that adjacent members shall be nonincident and that alternate members shall be distinct. This arrangement of lines and points enables us to establish a transformation relation the range of points [math]X[/math] on [math]o[/math] to the pencil of lines [math]x^{(n)}[/math] through [math]O_n[/math]. This is called a projectivity.