Exodus 26:15 (KJV)

And thou shalt make fifty loops on the edge of the one curtain that is outmost in the coupling, and fifty loops in the edge of the curtain which coupleth the second.

And thou shalt make fifty taches of brass, and put the taches into the loops, and couple the tent together, that it may be one.

And the remnant that remaineth of the curtains of the tent, the half curtain that remaineth, shall hang over the backside of the tabernacle.

And a cubit on the one side, and a cubit on the other side of that which remaineth in the length of the curtains of the tent, it shall hang over the sides of the tabernacle on this side and on that side, to cover it.

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

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 for the second side of the tabernacle on the north side there shall be twenty boards: