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Tricks with knots on the cord. Focus secret

Spectacular tricks and their clues

Directory / Spectacular tricks and their clues

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Focus Description:

All topological puzzles with cords begin with tying the hands with one piece of cord (Fig. 29). You can, for example, do such manipulations with the cord that a knot will appear on it; it can be ordinary or type eight. You can put a rubber ring on the cord and then remove it from the cord without untying or breaking the cord.

Tricks with knots on the cord
Ris.29

If two people are connected by hooked cords, as shown in Fig. 30, then the cords can be manipulated in such a way as to free them from the bundle.

Tricks with knots on the cord
Ris.30

The solution to all these puzzles is based on the fact that the ring formed by the cord, hands and body of the viewer is not really solid, but has breaks on the hands. To tie a knot on the cord, you need to do the following: form a loop on it, pass it from the inside under the ring tied to the hand, twist it once "(i.e. 180 °) and drag it back over the hand, pass it from the outside under the ring and drag above the arm forward. This forms an ordinary knot. The figure-eight knot will turn out in exactly the same way, but the loop must be twisted twice (360 °). passing under the rope ring, and then pulled over the hand and lowered onto the cord.By performing these manipulations in reverse order, you can, of course, remove the ring.

Two spectators, connected to each other as described above, are released as follows: the middle of the cord with which the hands of one spectator are tied is passed from the inside under the ring formed by the cord on the wrist of another spectator, pulled over the hand, and then passed back under the ring.

(Similar focus - Try to get free).

A very old trick with three beads strung on two threads put together is known as the "grandmother's necklace". (The idea of ​​this trick is also used in many other tricks with ribbons and cords.) The trick begins with the demonstration of beads strung on two strands put together. Then, when the viewer pulls on the ends, the beads fall from the threads into the hands of the demonstrator.

On fig. 31 shows in section how the beads should be strung. Although it seems that both strands are threaded through all three beads, in reality, each of the strands "comes back", folding with itself.

Tricks with knots on the cord
Ris.31

The ends of the threads are crossed, as shown in Fig. 32.

Tricks with knots on the cord
Ris.32

If you now pull on them (Fig. 33), the beads will fall off the threads.

Tricks with knots on the cord
Ris.33

Related to topology are many methods of cutting and "gluing" cords, as well as a number of ingenious ways of tying and untying knots in cords, the ends of which are kept pinched during the demonstration.

A typical knot among many curious false knots is the following. They begin to tie it like an ordinary double knot (Fig. 34), and then thread one of the ends of the cord into the lower and then into the upper ring, as shown in fig. 35.

Tricks with knots on the cord
Ris.34,35

If you now pull the ends, the knot will immediately untie.

Author: M.Gardner

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