Given two linearly independent length 3 vectors **a** and **b**, the cross product, \(\mathbf{a} \times \mathbf{b}\) (read "a cross b"), is a vector that is perpendicular to both **a** and **b** thus normal to the plane containing them.
xprod(...)
N-1 linearly independent vectors of the same length, N.
Returns the generalized vector cross-product, a vector of length N.
A generalization of this idea applies to two or more dimensional vectors.
See: [https://en.wikipedia.org/wiki/Cross_product] for geometric and algebraic properties.