Personalized Happy Pi Day Math Holiday Long Sleeve Creeper. Pi Day Long Sleeve Creeper - White has cute baked pie filled with math symbols. Fun shirt for students or teachers on Pi Day. For chillier weather, dress baby in this soft long sleeve creeper in a great fitting 1x1 baby rib. 5.0 oz., 100% combed ringspun cotton, 1x1 baby rib. White is sewn with 100% cotton thread, Flatlock seams, Double-needle stitched rib binding on neck, shoulders, sleeves and leg openings,Reinforced three-snap closure on binding.