Exodus 36:11-13

He made loops of blue yarn on the edge of the curtain on the selvedge of one set; likewise he did on the outer edge of the other curtain of the second set. Fifty loops he made on one curtain, and fifty loops he made on the edge of the curtain on the end of the second set; the loops held one curtain to another. And he made fifty clasps of gold, and coupled the curtains to one another with the clasps, that it might be one tabernacle.