2. Reverse figure-of-eight knot: first tie a figure-of-eight knot in the middle of the rope, first pass through the rope head, and then the rope head bypasses the main rope and passes through the rope loop before tightening. Next, thread the rope head through the rope head in the opposite direction of the knot. Then put the rope head through the first knot and return to the knot. Then in the process of winding back, the rope head needs to pass through the lower rope loop. Finally, just adjust the tension.