Personalized White Distressed Ruler Youth Long Sleeve T-Shirt. I am the ruler in distressed white text with a ruler replacing the letter L in ruler is a funny gift design for mathematicians and mathh teachers at back to school, birthdays and holidays. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)