The colorless picture shows 13 of those 'things' at the edges.
(the first or 13th just outside the frame)

This is wiki infomation I found on the subject.
Maya: "Vertically, the sky was divided into thirteen layers, while the underworld is often claimed to have consisted of nine layers."
Christian: / "Dante: Hell (underworld ) according to Dante consisted of nine cirkels."

* Could it be the 13 'things' represent the layers of heaven as they go upward? ( Maybe underground there are nine hidden going downward? ) I'd like to take that trip too. What first, backwards or forwards?