I don't have a picture of a naja to upload. Anyway...the stone relief on the wall is not a circle with a human in the middle (trying to break out?). It is a spiral! With the inner end wrapped around the middle section of a human form.
As for Naja symbology: (Hindu) "The Cobra, is a symbol of Kundalini power, cosmic energy coiled and slumbering within man. It inspires seekers to overcome misdeeds and suffering by lifting the serpent up the spine into God-Realization."
Naja was/is used by other cultures as a good luck charm to ward off the "Evil Eye".
The possible Naja symbols in Pinwheels room taken alone are interesting but when tied in with the stone relief spiral on the wall it becomes fascinating!
Thought I'd throw this out to the community for possible speculation!!