The Boston Herald (Mark Murphy) reports: J.R. Giddens is a man of many tattoos, but each, he says, have a purpose. A basketball encircled by a Black Mamba snake is tattooed over the Celtics rookie’s heart with the inscription, “Natural Born Killer” - an apparent reference to his playing style. But his newest - a green shamrock with the No. 4 behind his left ear - may also be one of his most dear. “I was the last pick of the first round,” he said. “Everyone had a chance to get me and they passed, and this is the team that took me. So I wanted to honor it.” Of his body art philosophy, Giddens said, “Some guys have tattoos all over that don’t mean anything. Mine all mean something.”