Wombats produce roughly one hundred cube-shaped droppings every single day. The bare-nosed wombat (*Vombatus ursinus*) shapes them in the final section of its intestine, where alternating stiff and flexible muscle bands press the drying dung into flat edges. Depositing these geometric blocks on elevated rocks and logs keeps scent markers from rolling away. It is the only known creature that manufactures right angles inside its digestive tract. More