Personalized Third Grade Rocks Toddler Long Sleeve T-Shirt. Third grade rocks text with three happy rocks holding 3rd grade flags is a funny design for back to school, 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.