Does successive multiplications of each element in `args'. If two
elements are scalar, then their product is i * j, if a scalar is
multiplied by a matrix, then each element in the matrix is multiplied
by the scalar, lastly, if two matrices are multiplied then standard
matrix multiplication is applied, and the ranks must be such that if
ARGi is rank a x b and ARGj is rank c x d, then b must be equal to c.