Exodus 26:14-18

And thou shalt make a covering for the tent of rams’ skins dyed red, and a covering above of badgers’ skins.

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.