Personalized Happy Pi Day Robot Math Class Newborn Layette. Pi Day Newborn Layette - White has funny vintage style robot and math symbol Happy Pi Day celebration logo. 100% combed ringspun cotton 5.8 ounce 1×1 baby rib sleeper. 3/8" flatlock binding at envelope neck and cuffs. Back sleeve flap to protect hands. Elastic opening at bottom. Infant: 0-3 Months