code: def concatenate_matrices(*matrices):
      
      M = numpy.identity(4)
      for i in matrices:
          M = numpy.dot(M, i)
      return M
docs: Return concatenation of series of transformation matrices.
  
      >>> M = numpy.random.rand(16).reshape((4, 4)) - 0.5
      >>> numpy.allclose(M, concatenate_matrices(M))
      True
      >>> numpy.allclose(numpy.dot(M, M.T), concatenate_matrices(M, M.T))
      True