Cephalopod skin is controlled in fine spatial detail, since each chromatophore is driven by its own motor neurons. Sepioteuthis sepioidea exploits that resolution for split displays: the two flanks carry different patterns at the same time, divided along the midline.
The situation is specific. A male flanked by a female on one side and a competing male on the other has been observed showing the pale, striped courtship pattern towards the female and the dark, high-contrast agonistic pattern towards the rival. If the animals swap sides, the male reverses the two patterns. The behaviour is well described in reef squid and in some cuttlefish, and it requires the receivers to be positioned so each sees only one flank.
The commonly attached interpretation, that this proves the squid intends to deceive the rival, goes beyond what the observations establish. What they show is independent bilateral control of skin patterning applied appropriately to two audiences. Whether the sender models what the rival knows is untested, and it is worth noting the same species also uses these patterns outside any courtship context.