Peekaboo Monkey!

We recently got Lincoln a mirror for his toy corner to encourage his tummy time. It's working a little, but he loves sitting up to play peekaboo most of all. He really understands the mirror. He watches monkey appear in the mirror then turns his head to find him. Olive on the other hand, does not understand the mirror. She thinks we bought another cat but she just can't work out where it is.