A Puzzle For You…
Help me solve this damned thing!
It starts like this…
And ends like this (except you smart people out there will not have a line segment you haven’t left uncrossed like mine, highlighted in yellow)
A childhood friend named Larry shared this with me on the school bus one day (must have been in 1977). He said his grandfather would pay him $50 if he could solve it.
I’ve been ruining notebook after notebook for THIRTY years trying to solve this on paper. Probably easily done with a clever program. But, my brain’s not a clever enough program (or fast enough, take your pick). Help stop my madness. Please!
RULES
You must cross each line segment of the boxes once and ONLY once.
You may start at any place inside or outside of the boxes.
You may cross your own line without restriction (in this example my own line is red).
You may not create any more than one continuous line (meaning you cannot create branches from your original line).
You may not traverse your own line, effectively crossing the line segment of any box for a second time.
PRIZE
Bragging rights and my unending thanks for putting an end to a 30 year long obsession. This will be up there with stopping smoking or biting fingernails or some such other disorder of ill repute. If I knew where Larry was I’d have him split the $50 with you. 
September 7, 2007 at 6:16 pm
Larry’s grandfather’s $50 was perfectly safe all along; it’s impossible to solve this puzzle.
It’s a very well known problem and this web page explains why it can’t be done http://www.mazes.com/puzzles/5-rooms/index.htm
Sorry you wasted all those notepads!!
[feel free not to approve this comment so as not to spoil the fun for others!]
September 8, 2007 at 7:42 am
@Mark – Spoil the fun!? Bloody hell! I’ve spent a couple weeks (solid) of my life all told trying to solve something with no chance of solving it. I’ll sure let others know! Particularly friends and family I’ve infected with this little doozy.
Now, if only I knew where Larry was… I’d let him have it!
September 8, 2007 at 1:52 pm
Thanks Mark, you probably saved my life
I was just about to eat something, when gwhiz posted that puzzle. Since then I am starving and already lost 3 A4 pages to that!
September 8, 2007 at 3:54 pm
Pawel – So sorry about that little diversion. When Mark commented I knew I couldn’t string another generation along. I should have given in a long time ago to find the solution… Some puzzles are more fun without the extra help. In this case I was clearly wrong.
September 9, 2007 at 2:13 am
I wasted a few hours on this myself last night Mr Buckley! Eventually though I decided it wasn’t possible and gave up on it. Glad I did now, heh!
Still, it’s a good little story
All the best,
- Al / DivX
September 30, 2007 at 11:06 pm
Thanks for sharing the puzzle. I played with it for a little while before checking the comments to confirm what I suspected. Thanks too for the great blog. I read it for the first time tonight. Good luck with the AWS challenge!