Personalized Happy Pi Day Pink Math Symbol Long Sleeve T-Shirt. Cute pink pi math symbol with stitch border on a Long Sleeve T-Shirt - Charcoal with Happy Pi Day quote. Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL