The art director chose an artist who was a scientist and paleoartist to create photorealistic illustrations of T. rex in three stages of growth, with depictions based on the growing body of research regarding these dinosaurs. One design illustrates a face-to-face encounter with a T. rex approaching through a forest clearing; another shows the same young adult T. rex with a young Triceratops—both dinosaurs shown in fossil form. The third and fourth stamps depict a newly hatched T. rex covered with downy feathers and a bare-skinned juvenile T. rex chasing a primitive mammal. Two of the stamps were printed with a lenticular effect to reveal additional images—a fleshed out version of the T. rex skeleton and the predatory T. rex advancing.
