Exodus 26:18-21

18You shall make the boards for the tabernacle: twenty boards 1for the south side.

19You shall make forty 2bases of silver under the twenty boards, two bases under one board for its two tenons and two bases under another board for its two tenons;

20and for the second side of the tabernacle, on the north side, twenty boards,

21and their forty bases of silver; two bases under one board and two bases under another board.