Ezekiel 41:8

And the side chambers were three, one over another, and thirty in order; and they entered into the wall which was of the house for the side chambers round about, that they might have hold, but they had not hold in the wall of the house.

And there was an enlarging, and a winding about still upward to the side chambers: for the winding about of the house went still upward round about the house: therefore the breadth of the house was still upward, and so increased from the lowest chamber to the highest by the midst.

The thickness of the wall, which was for the side chamber without, was five cubits: and that which was left was the place of the side chambers that were within.

And between the chambers was the wideness of twenty cubits round about the house on every side.