Personalized Pi Day Funny Math Pie Slice Infant Romper. Funny every day is a good day for pie Pi Day Infant Romper - Black math shirt. 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)