I only see one

There is a square behind them The background color on the right is slightly different The nose color on the right is also slightly different

light switch? only in right right background is darker nose or mouth is different colors

Square behind head, Background color, mouth color

1. door thingy on head 2. different colors in background 3. different colors in nose

There is a light switch, one of the rooms is darker, and one of the noses is darker.