The applet below is a game board for a puzzle. The task is to place eight digits 1 through 8 into eight circles, but there is a caveat. Some of the circles are connected as shown and, for this reason are considered neighbors. The numbers should be placed so that no two successive digits are placed into neighboring circles.

The applet keeps for you the count of the assigned digits. You should only decide where to place the next digit. You do that by clicking on the circle of your choice. You can remove the last placement either by clicking on the corresponding circle or by pressing the "Step back" button at the bottom of the applet. The applet also warns you whenever you place two successive digits into neighboring circles.

Solution

References

1. M. Gardner, The Unexpected Hanging and Other Mathematical Diversions, Chicago University Press, 1991
2. M. Gardner, The Colossal Book of Short Puzzles and Problems, W. W. Norton & Company, 2006, p. 6

Copyright © 1996-2008 Alexander Bogomolny