Some point-group specific concerns are necessary when dealing with E-or T-symmetric modes; for example, in D4h the number of possible Eg-mode orientations is 4, on x, y, x+y and x-y (C' and C'') axes, where only two are necessary for a complete description of the system. The sum of these modes is multiplied by ½ to arrive at the correct atom positions, and the Mondrian diagram uses only the greatest magnitude vector and its orthogonal counterpart to describe the symmetry of the molecular component. This is achieved by using the derived eigenmodes as input vector sets in a pseudo-normal coordinate analysis, which is the simple_scsd output of the scsd_matrix object.