|DIRAC'S STRING PROBLEM|
Dirac's String Problem
To back of bag
Translation of the front of the bag
A bottle opener is attached to two posts (e.g. two table legs) by elastic strings (or loose strings) as shown in Figure 1 [see below].
Now turn the bottle opener another full turn, so that altogether we have made two full turns (Figure 3).
In Figure 3 everything looks a bit more twisted. Again keep the bottle opener fixed and see whether the twisting can now be removed by taking the strings over and around the bottle opener. This time it is possible to do it. If you give up, the solution can be found on the other side of the bag.