ENCYCLOPEDIA  OF  QUADRI-FIGURES   (EQF)    This  encyclopedia  is  dedicated  to  Quadri-figures. A QUADRI-FIGURE is a figure consisting of 4 points and/or 4 lines.

 E Q F - D E F I N I T I O N S P R O P E R T I E S A quadrangle is a geometrical figure consisting of 4 points. There is no order in these points. Abbreviation: QA A Quadrangle has: 6 connecting lines 4 component triangles 3 component quadrigons 1 diagonal triangle Quadrilateral points and other objects A quadrilateral is a geometrical figure consisting of 4 lines. There is no order in these lines. Abbreviation: QL A Quadrilateral has: 6 intersection points 4 component triangles 3 component quadrigons 1 diagonal triangle Quadrigon points and other objects  A quadrigon is a geometrical figure consisting of  4 consecutive points and 4 consecutive connecting lines.  There is a cyclic order in these points & lines. Abbreviation: QG A Quadrigon has: 2 pairs of opposite lines 2 pairs of opposite points 2 diagonals 1 third diagonal 1 diagonal crosspoint The results of EQF also can be downloaded as a PDF-file: