Exodus 26:23

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

Two boards shall you make for the corners of the tent in the far part.

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

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

and two frames for the two back corners of the tabernacle,