Personalized Structural Engineering Smile Youth 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. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.