of wool and linen all the time. From this perspective, the of the layman reflects that of the priest. In practice, the rabbinic sages permitted using wool and linen strings in tandem only when what they hold to be genuine tekhelet is available. Threads and knots The tassel () on each corner is made of four strands, which must be made with intent. These strands are then threaded and hang down, appearing to be eight. (It is customary that each of the four strands is made of eight fine threads, known as ). The four strands are passed through a hole (or according to some: two holes) 1-2 inches (25 to 50 mm) away from the corner of the cloth. There are numerous customs as to how to tie the tassels. The Talmud explains that the Bible requires an upper knot () and one wrapping of three winds (). The Talmud enjoined that between seven and thirteen be tied, and that "one must start and end with the color of the garment". As for the making of knots in between the , the Talmud is inconclusive, and as such later poskim have interpreted this requirement in various ways. The Talmud described tying assuming the use of dye. Following the loss of the source of the dye, various customs of tying were introduced to compensate for the lack of this primary element. The tying method which gained the widest acceptance can be described as follows: The four strands of the are passed through a hole near the garment's corner. The two groups of four ends are double-knotted to each other at the edge of the garment near the hole. One of the four strands (known as the ) is made longer than the others. The long end of the is wound around the other seven ends and double-knotted; this is done repeatedly so as to make a total of five double knots separated by four sections of winding, with a total length of at least four inches, leaving free-hanging ends that are twice that long This tying procedure is used for each of the garment's four corners; if it has more than four corners, the four that are farthest apart are used. In Ashkenazi custom, the four sections of winding number 7-8-11-13 winds, respectively. The total number of winds comes to 39, which is the same number of winds if one