A : 1
B : 2	C : 3	D : 4
E : 5	F : 6	G : 7
	H : 8

Arrange the numbers in the grid above in such a way that no two adjecent cells (horizontally, vertically or diagonally) have consecutive number in them. For example 1 must not be next to 2. (The letters are shown so that you can easily refer to specific individual boxes.)

(From: http://www.ocf.berkeley.edu/~wwu/riddles/intro.shtml)

There are four differnt correct solutions, but they are all reflections/rotations of one another: for example, you can switch the numbers in boxes A and H, if you also switch C with F, etc.

These are the instructions for one of the four. By making diffent choices at the points marked with an asterisk (*), you will get the other three.

The first thing to notice is that there are only eight different numbers, but boxes C and F each have six neighbors. That means the numbers that go in them can only have one other number next to them in sequence. That means 1 and 8.

Put 1 in C and 8 in F*. Now 2 must go in H and 7 in A. Three can go in either B or D. Let's put it in D*. If we put 6 in G, then 4 and 5 are next to each other, so it must go in E. Then 5 goes in G and 4 in B.

Posted by TomM on 2003-01-10 07:35:17