Personalized Structural Engineering Smile T-Shirt. Structural engineering text forming a smiling face with the text makes me smile is a humorous structural engineering design for birthdays, holidays nad graduation. Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.