It may be entirely unlike Zack's face markings, but Alec's tattoo has always reassured him some. Another being with facial markings seemed appropriate to have as a friend. In fact, back in Antillioch, Zack did spend a few hours trying to make his red marks appear blue. Without success.

It tends to stop people staring at them, or so Zack likes to think. Safety in numbers.

He's about to grin at Alec, and remark on what a piece of cake that was, only in fun; but the comment makes Zack balk.

“Different?” His hands go to his face. He hadn't stopped to think about that... ”Different how?” He already knows the answer and doesn't want to hear it. At the same time, he needs the confirmation.