Exodus 25:35

For the six branches that extend from the lampstand, a bud must be under the first pair of branches, a bud under the second pair, and a bud under the third pair.

And there shall be a knop under two branches of the same, and a knop under two branches of the same, and a knop under two branches of the same, according to the six branches that proceed out of the candlestick.