@tokensane
Possible, though an adult would be hard pressed to slip through the opening.

I also think it's sideways here, and the two smaller holes go in either the "top" or "bottom" position.

Another possibility is it's a floor piece for a (water?) gate of some sort. There was a Palace Mill at several different times.

#NotAnArcheologist

@TiciaVerveer @ixi
My theory is that this was done to indicate whose sling stone was whose in the policing up after the hunting party, or whose stone was closest to the target in games, much like golfers mark their balls today.

Good sling stones were a valuable item, and status symbol, of sorts.

#NotAnArcheologist