More generally, this would be 6D since each of the two points have x,y,z coordinates, but because the two points are confined to the planes shown above, we only need to specify x,y and u,v, reducing the dimensionality to 4D.

More generally, this would be 6D since each of the two points have x,y,z coordinates, but because the two points are confined to the planes shown above, we only need to specify x,y and u,v, reducing the dimensionality to 4D.