Ezekiel 41:7,8

And there was an enlarging Namely, of the side-chambers; so much of breadth added to the chambers as was taken from the thickness of the wall: see the preceding note; and a winding about still upward Winding stairs, which enlarged as the rooms did, went up between each two chambers from the bottom to the top; and there were two doors at the top of each pair of stairs, one door opening into one chamber, and the other into the opposite one. For the winding about, &c. The stairs, as they rose in height, enlarged themselves too; round about the house On all sides of the house, where these chambers were. Therefore the breadth was still upward It became broader by one cubit in every upper chamber. I saw also the height of the house Of the chambers which rose to three stories high. The foundations, &c., were a full reed of six great cubits The lowest chamber had properly a foundation laid on the earth, but the floor of the middle and the highest story must be accounted here a foundation; so from the ground to the ceiling of the first room were six great cubits; from the first to the second, six great cubits; and from the third floor to the roof of the chamber, a like number; to which if we add one cubit for the thickness of each of the three floors, you have twenty-one cubits, or ten yards and a half for height.