14. ANSWER TO THE CABINET-MAKER’S PUZZLE.
The cabinet-maker must find the centre of the circle, and strike another circle, half the diameter of the first, and having the same centre. Then cut the whole into four parts, by means of two lines drawn at right angles to each other, then cut along the inner circle, and put the pieces together as in the above [diagram].
15. ANSWER TO THE STRING AND BALLS PUZZLE.
Draw the loop well down, slipping either ball through it. Push it through the hole at the extremities, pass it over the knot, and draw it through again. The same process must be repeated with the other ball; the loop can then be drawn through the hole in the centre, and the ball will slide along the cord until it reaches the other side. The string is then replaced, having both balls on the same side.
This plan of passing the loop over the knot is a key to all the puzzles of this nature.
There is another and perhaps a neater way of performing this trick. Draw the loop through the central hole, and bring it through far enough to pass one of the balls through. Having done this, draw the string back, and both balls will be found on the same side.