Yes and No

Buddy has reached the "No phase" where every answer is "No!".  One night a week or so back he got going on a string of "No!"s.  So, I asked him "Can you say anything but no?"  "No!"  "Can you say yes?" "No!"  "Can you say no?"  He freezes with this "processing, processing..." look on his face, then giving a sly little smile NODS his head yes.  It was hilarious (though I admit I was very surprised - smart little bugger)!