Plane direction

In Euclidean geometry, a plane is a flat two-dimensional surface that extends indefinitely. Euclidean planes often arise as subspaces of three-dimensional space R 3 {\displaystyle \mathbb {R} ^{3}} . A prototypical example is one of a room's walls, infinitely extended and assumed infinitesimally thin. While a pair of real numbers R 2 {\displaystyle \mathbb {R} ^{2}} suffices to describe points on a plane, the relationship with out-of-plane points requires special consideration for their embedding in the ambient space R 3 {\displaystyle \mathbb {R} ^{3}} .