The carvings signifies symbols in Buddhism.  In the hub of the wheel are three animals: a pig, a snake, and a bird. They represent the three poisons of ignorance, attachment, and aversion. The pig stands for ignorance; this comparison is based on the Indian concept of a pig being the most foolish of animals, since it sleeps in the dirtiest places and eats whatever comes to its mouth. The snake represents aversion or anger; this is because it will be aroused and strike at the slightest touch. The bird represents attachment (also translated as desire or clinging)whereas  here in this craft, in the middle Buddha's statue is created, to make one realization of enlightenment and not to rotate in  circulation of Samara instead of pig,bird and snake. It is a Sanskrit word which means time wheel.  In Buddhism  this wheel is the symbol of Kalachakra tradition that  teaches the practice of working with the most subtle energies within one's body on the path to enlightenment. It is a wood specie from Gmelina Arborea.