It looks like Cooper is starting to really stick up for himself. Today he slapped Cash across the face and laughed. i know he didn't do this on purpose but its hard to explain that to Cash. he loves to chase Cash around - the two of them can really get into trouble fast, running around, slamming doors.
He copies Cash in all sorts of things. making noises, facial expressions are two things i noticed today that Cooper did right after Cash did them.
Today i also caught him dragging the laundry basket over to the window, flipping it upside down and climbing up on it. he stood on it and looked out the window for quite a few minutes before thought it would be funny to fall off - hoping that someone would catch him. (we did).
He also loves to call out for Cash. whenever Cash isn't in the room or Cooper is looking for him, he'll call "Cash" until he finds him.