Function matmath::special_matrices::projection::parallel_projection_matrix

pub fn parallel_projection_matrix<T>(
    from_dim: usize, 
    embedded_axis: Vector<T>
) -> Matrix<T> where
    T: MatrixElement + Clone, 

This builds a matrix that sets a vector in (n-1)-D space as the base vector for the last axis in n-D space.

You have done this by hand if you've ever drawn a 3d coordinate system on paper (the 3rd axis is kind of diagonal there)