I mean this
Here's what I meant by prodcut of direction vectors.
direction vector L1 = (2,-1,3)
direction vector L2 = (-3,2,-1)
Thus D.V. L1 * D.V. L2 = det( i j k ) = (-5,-7,1)
.........( 2 -1 3 )
........ ( -3 2 -1 )
forgive me for using parenthesis where abstract value sign...