QG-1: Systematics for describing QG-Points

A Quadrigon is also often called a Tetragon.
In the descriptions of EQF these are the definitions of these terms:
• A Quadrangle is a system of 4 random points without conditions. It also often is called a Complete Quadrangle.
• A Quadrilateral is a system of 4 random lines without conditions. It also often is called a Complete Quadrilateral.
• A Quadrigon is a system of 4 consecutive points and 4 consecutive connecting lines. It is also called a Tetragon. There is a cyclic order of points and lines, meaning here that the permutation of 4 points in a certain order equalizes the permutation of 4 points in the reversed order. When the order in a permutation of a cycle equalizes the permutation with reversed order we will name this condition “vv-cyclic” (“vv” stands for “vice versa”).
Within a Quadrangle (4 random points) 3 permutations can be discerned of 4 vv-cyclic consecutive points.
Within a Quadrilateral (4 random lines) 3 permutations can be discerned of 4 vv-cyclic consecutive lines.
It can be seen as the “intersection“ of a Quadrangle and a Quadrilateral. 