This article is about the geometrical figure. Not to be confused with Plane.
The Euclidean plane is a flat, infinitely large two-dimensional space following the rules of two-dimensional Euclidean geometry. It can be formed from the Cartesian product of two copies of the Euclidean line.
A plane can be used to bisect a cell, and cells can have planes of symmetry through which they are reflected. The place at which a cell intersects a plane gives a two-dimensional shape and the change in shape as the cell passes through the plane can give information about the structure of the cell.
There is more than one way to make a 2D Cartesian plane. You could say the lines should be slightly slanted, as long as they parallel.