Jens loves tapping his hands on anything. His Nans called it playing the piano if he's doing it on the table and playing the drums if on a chair.
Mcj used to teach him to knock on the door and he would do it with palm open. Recently, his Dad taught him to properly knock. And Jens had learned very quickly.
Now, Jens knows how to knock on the door even if he's inside. :) And instead of tapping to table or the chair sometimes, he would knock on them.
I just love looking at him doing it!