Classic puzzle
 

I THINK it's a classic:
[code]
* * *
* * *
* * *
[/code]
Connect the 9 dots with 4 lines

Forgot: [b][size=7]WITHOUT PICKING UP YOUR PEN[/size][/b]

Too easy. One line will do. Just make it curve around as needed to move from one row to the next.

Oh! You want us to use 4 connected straight line segments.
That's a little harder :)

I believe that the classical statement of the problem describes the 9 points as trees in an orchard.

classic puzzle
 

:yawn: They should be 4 straight lines to make it even harder.
[spoiler]Start with a diagonal and (say the right hand lower corner one) and go up this diagonal connecting to the top lefthand upper corner. Then draw the horizintal line connecting the 3 upper dots and move OUT of the square till its in line with the other three forming the straight line down to the left hand lower corner dot . What remains is the left side of 3 dots. Connect them and you have solved the problem. Try it any way but you must get OUT of the square. Most people restrict themselves only within the square .[/spoiler] :banana:
Mally :coffee:

It is a puzzle psychiatrists (sp?) often use to show how lateral thinking and perspective vaalutation may improve your vision of yourself. :innocent:

Luigi

Classic puzzle
 

:smile: How right you are luigi and thanks for refreshing my mind on lateral thinking.
Dr. Edward de Bono is a pioneer in this field.
This is what he says about this particular problem in his book 'Lateral Thinking'
"The assumption is here that the straight lines must link up the dots and must not extend beyond the boundaries set by the outerline of dots. If one goes beyond the boundary the problem is easiy solved"
As you rightly say this problem can guage a person if he/she is an introvert or an extrovert. The ideal would be to strike an even balance of mind. :razz:
Mally :coffee:

Yeah, I knew this one already, so I cannot but post my standard reply: To make it a little harder, connect the nine above dots with
[SIZE=7]3 straight lines[/SIZE]!!!
Enjoy, :wink: H.

[QUOTE=hhh]Yeah, I knew this one already, so I cannot but post my standard reply: To make it a little harder, connect the nine above dots with
[SIZE=7]3 straight lines[/SIZE]!!!
Enjoy, :wink: H.[/QUOTE]

Can you pick up your pen? Is this a Euclidean geometry problem?

[QUOTE=rogue]Can you pick up your pen? Is this a Euclidean geometry problem?[/QUOTE]

Me thinks "hhh" is just a crank

[QUOTE=Wacky]Me thinks "hhh" is just a crank[/QUOTE]

That might be true, but the question begs an answer. If you can pick up your pen, then the solution is obvious. If you cannot, then the solution depends upon whether or not you are using Euclidean geometry. AFAIK, in Euclidean geometry there is no solution, but that doesn't mean that there is no solution in non-Euclidean geometry. So if we expand the scope of the problem to hyperbolic geometry or spherical geometry, the answer could be (and probably is) different.

Or hhh assumes that the dots have positive area.

Alex