Personalized Pi Day March 14 Math Lover Science Drawstring Bag. Whether you're attending a math-themed party or just want to express your geeky side, this Pi Day apparel is a must-have. Grab yours today and wear your love for math proudly! A durable and versatile cinch bag built to handle daily use. . With its lightweight design and reinforced corners, this pack is perfect for the gym, travel, or everyday activities.