In Figure , we plot the components of the two selected orbital-gradient pairs. In the left column, we plot ∇ψa as a yellow-purple vector field of the HOMO and the HOMO-1 in the top and bottom row, respectively. We have super- imposed ψa on top of the vector field in transparent red and blue. Across the nodes, there are large gradients (large arrows) as we go from an area with a positive phase to a negative phase and vice versa.