I heart you

Recently I noticed a new addition to the (sparsely decorated) wall above Leo and Pax's beds.  I asked Pax, "Who put that heart up on your wall?"
          "I did," he replied.  [using a ginormously sharp, oversized thumb tack]
"Um.... okay.  What made you decide to do that?"
          "Well, I put it up there because when I am feeling sad - like when I have to go to my room because I am in trouble - I can look at it and think about love."