The 22 dots in the figure below can be connected by 11 lines, each beginning and ending with a dot (o) and passing through 4 empty cells. Connecting lines may proceed horizontally or vertically, but not diagonally. They may change direction as often as needed, and they should not cross one another.

               +---+---+---+---+---+---+---+---+
               |   | o | o |   |   | o |   | o |
           +---+---+---+---+---+---+---+---+---+---+
           |   |   | o | o | o |   |   |   |   |   |
           +---+---+---+---+---+---+---+---+---+---+
           |   |   |   |   |   | o |   |   |   | o |
           +---+---+---+---+---+---+---+---+---+---+
           | o |   |   |   |   |   |   | o |   | o |
           +---+---+---+---+---+---+---+---+---+---+
           | o |   |   | o |   |   | o | o |   |   |
           +---+---+---+---+---+---+---+---+---+---+
           | o |   |   | o |   | o |   |   |   |   |
           +---+---+---+---+---+---+---+---+---+---+
               |   |   | o |   |   |   | o | o | 
               +---+---+---+---+---+---+---+---+

Can you do it?

(In reply to Graphic Design by brianjn)

"I jumped to the conclusion that the lines must be "straight"!"

brianjn, but itīs written :"they may change directions as often as needed". I think you missed this.

I think too that we have very few tools to post a solution, or even to post a problem that requires a different drawing. It would be more easy if we could "aggregate" a drawing to the problems or to the answers we post.

I donīt know how Joe achieve his solution, but we can see, even in this kind of problem, some logical thinking in Lisaīs solution. 

Posted by pcbouhid on 2005-08-15 14:42:37