Personalized Coolest Mechanical Engineer Toddler Long Sleeve T-Shirt. The world's coolest mechanical engineer text with a snowman holding a gear and sporting a hat and scarf with gears is a humorous engineering gift design for birthdays and holidays. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.