Personalized Nuclear Ornaments Toddler Long Sleeve T-Shirt. A green tree with radioactive symbols instead of ornaments is a unique gift design for college students, physicists, environmentalists, nuclear engineers and workers at 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.