If you flatten a 3D object's XYZ coordinate system into a 2D image, you'll receive UVW space. UV coordinates consist of "U" that represents the horizontal axis, "V" that stands for the vertical axis, and "W" that is for the depth. "Why do I need to care about depth in 2D?" The thing is, each UVW coordinate has a corresponding point in 3D space — a vertex. In turn, the "W" coordinate ensures each vertex is displayed correctly in 3D if there's rotation, scaling, shearing, or offset.^[1]