The individual sections of the dorsal side of a chelonian (turtle / tortoise / terrapin)'s shell are called scoots.
As the animal grows, its shell grows, and it molts. Similarly to how a snake sheds its skin, a chelonian sheds its scoots.
This clever owner collected all of the scoots from one molt, and made an art piece out of them.
(That's Sergio the turtle, for comparison.)










