Personalized Programmer's Paint by Number Toddler Long Sleeve T-Shirt. A paint by number for computer geeks with hexadecimal numbers is a fun design for birthdays, holidays and graduation. 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.