Exodus 26:20 (KJV)

And thou shalt make boards for the tabernacle of shittim wood standing up.

Ten cubits shall be the length of a board, and a cubit and a half shall be the breadth of one board.

Two tenons shall there be in one board, set in order one against another: thus shalt thou make for all the boards of the tabernacle.

And thou shalt make the boards for the tabernacle, twenty boards on the south side southward.

And thou shalt make forty sockets of silver under the twenty boards; two sockets under one board for his two tenons, and two sockets under another board for his two tenons.

And their forty sockets of silver; two sockets under one board, and two sockets under another board.

And for the sides of the tabernacle westward thou shalt make six boards.

And two boards shalt thou make for the corners of the tabernacle in the two sides.

And they shall be coupled together beneath, and they shall be coupled together above the head of it unto one ring: thus shall it be for them both; they shall be for the two corners.

And they shall be eight boards, and their sockets of silver, sixteen sockets; two sockets under one board, and two sockets under another board.