The figure below shows the molecular models of (a) trans-2-butene and (b) cis-2-butene, where two sp² carbon atoms are connected to each other with #4 bond (1.40 Å, σ bond). In addition, these sp² carbon atoms are also bonded with π-bond represented with p-atomic orbital plates (green and blue), as shown. It should be noted that in these models, green orbital plates are connected to each other with a green orbital connector, and blue orbital plates are similarly bonded with blue connector. Therefore, the rotation around the C=C double bond is blocked. Thus, the orbital connectors are useful for differentiating trans- and cis-olefin isomers, as exemplified here.

Geometrical isomers of olefin compounds: (a) trans-2-butene. (b) cis-2-butene. In these molecular models, the orbital connectors block the rotation around the C=C bond, and hence they are useful for differentiating trans- and cis-olefin isomers.