Perspective (geometry): Collinear, Point, Desargues' Theorem, Shape

Moulton Plane: Geometry, Affine Plane, Desargues' Theorem, Forest Ray

Menelaus' Theorem: Menelaus of Alexandria, Plane Geometry, Triangle, Collinear

Simson Line: Geometry, Triangle, Point, Circumcircle, Collinear, Robert

General Position: Algebraic Geometry, Generic Property, Point, Collinear