Both are "chocolate-on-my-note" ~
The one on the left is received from Prof. Tim Flaherty during the Lecture of Concepts of Mathematics (21-127) on the Valentine's Day of 2014. We were discussing the Logic section at that time.
The one on the right is received from Prof. Michael Erdmann during the lecture of Function Programming, when we were discussing the Game Nim.
Labor day weekend Nile visited me ~