the wrist loop on the other side of B's wrist, passing this time from the distal to the proximal side. A can now pull his own string clear of B on the outer side of B's arm (Fig. 12).
The principle of this trick is the same as that of many wire puzzles, of which two common forms, Fig. 13, are figured. I got this trick from a book, I cannot remember where, some time in the seventies.
The Finger String-Trick.
Place the loop over the right index and over the index of another person (B), the strings extended parallel, both indices upright. Press the left index on both strings half way (Fig.
14), and, holding them firmly down, move the right index in a circle over it until the index tip meets the tip of B's index (Fig. 15). Pull the strings with the left index, and slip its