To illustrate: In the conventional view and as shown in Scheme 1, the forward reaction direction decreases the ethylene and butadiene C=C bonds from double to single bond order, while increasing the butadiene C2-C3 bond single to double. At the TS (Scheme 4), the ethylene and butadiene C-C bonds will have an intermediate bond order between 1 and 2, while the inter-molecular C1-C5 and C4-C6 bonds will have a bond order between 0 and 1.