Two soldiers, William and Ethan, are assigned to guard a bridge, which connects the West and East sides of the Great Kingdom. Each soldier is ordered to stand at an end of the bridge to make sure no criminals cross.

On one side of the bridge stands William, watching over the West side of the kingdom, and making sure no shady characters try to cross the bridge.

Ethan stands on the other side of the bridge, facing the East side of the kingdom with his rifle at the ready in case any criminals try to pass across.

"Any criminals today?" William asks.

Ethan rolls his eyes. "What do you think?" he asks.

"You roll your eyes too much," William says.

How could William tell that Ethan was rolling his eyes?