Personalized Physics Heart Dark Products Toddler Long Sleeve T-Shirt. Physics text with a large P and a heart dotting the i in physics is a fun gift design for students, teachers and physicists at birthdays, holidays, back to school 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.