<m.Shabbath 13.2>  

He who makes two meshes, attaching them either to the cross-pieces [nirim] or to the slips [keros], or in a winnow, sieve, or basket, is culpable. And he who sews two stitches, and he who tears in order to sew two stitches [is likewise culpable].

(Purchase a printed Mishnah)