Personalized Quantum Mechanics Building White Youth Long Sleeve T-Shirt. Quantum Mechanics Building text with you are here arrows pointing to two different locations is a humorous quantum physics design for science geeks at back to school, birthdays, holidays and graduation. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)