Another thing you might do is to make 8 thin lines twice as long as you need the 16 lines to be, and lay them parallell with the thicker line. Then tie around the middle of the bundle of thin lines (with the thick line between them all) with a constrictor or a strangle knot, using some thin, strong line. Then fold the upper halves of the thin strings down. Now you have your 16 lines coming out from approximately the same point on the thicker line. Then you make some half hitches just below the constrictor to keep everything in place and give it a neat look. Even better is something like a whipping. If the half hitches aren't many enough, or if the material is slippery, you can keep the whole bundle from sliding down the thick line by tying a double overhand knot on the thick line, just below the right height for the origin of the thin lines. Maybe it's best to make the 8 lines a bit longer than they are supposed to be, because there is always some unevenness you might need to trim off.
