Stairway grid types

Variables
const int	Bottom = 2
	Bottom faces of a stairway.
const int	Cut = 5
	Faces appearing as a result of cutting a stairway by other objects.
const int	LeftSide = 3
	Left side faces of a stairway (when looking at the starting point towards the end point).
const int	RightSide = 4
	Right side face of a stairway (when looking at the starting point towards the end point).
const int	Top = 1
	Top faces of a stairway.
const int	Undefined = 0
	Undefined.

Possible grid types for a Stairway mesh