Ezekiel 41:5-7

5Next, he measured the wall of the temple, six cubits. The width of each side chamber all around the temple was four cubits on every side.

6The side chambers were in three stories, one above the other, thirty chambers in each story; they rested on ledges which were for the side chambers all around, that they might be supported, but not fastened to the wall of the temple.

7As one went up from story to story, the side chambers became wider all around, because their supporting ledges in the wall of the temple ascended like steps; therefore the width of the structure increased as one went up from the lowest story to the highest by way of the middle one.