He knew his brother loved him - well, they were brothers - but this?
He sat down to wait for Elrohir, who had gone on a hunting expedition, with the unexpressed aim of killing any Orcs he might stumble across in the process. He was expected back within the day.
For this, Elladan could wait.
Eventually, Elrohir returned, and Elladan confronted him.
"You have been sketching me without my knowledge, brother. And you have been doing it frequently. Why?"
"I believe you already know the answer, my brother."