Personalized Happy Pi Day Math Lover Party Infant Romper. Pi Day math themed Infant Romper - Black has pi symbols in a pie. Fun gift for a geek, math teacher, college math major or any math lover. Meet your new favorite outfit! Keep dressing simple with this one piece, lap shoulder t-romper. Super soft and perfect for baby's sensitive skin. 5.5 oz. 100% combed ringspun cotton premium jersey (CVC Colors are 60/40; Heather is 90/10 combed ringspun cotton/polyester)