Show off your love for math with this unique black t-shirt. The shirt features the formula "B₄(p) := {x ∈ M | d(p, x) < r}" printed in white across the chest. Made from a comfortable material, this tee is perfect for students, teachers, or anyone who appreciates mathematical concepts. The simple yet eye-catching design makes it suitable for casual wear, math meetups, or as a conversation starter. It's sure to spark intellectual discussions wherever you go. Get yours today and wear your passion for mathematics!