Personalized Pi Math Day grunge Youth T-Shirt. Pi Math Symbol Youth T-Shirt - Red has fun grunge look. graphic licensed from and c. www.graphicsfactory.com Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.