The 9 dot puzzle.

The Dagda

This ones a classic and it doesn't seem it's come up before.

But draw 9 dots in 3 rows and columns that are equidistant, now join them up with not more than 4 straight lines.

If you already know it be sure not to give the game away. Just a simple problem I thought might pass a few moments to those who haven't seen it before.

Proton Soup

i'm not sure i understand the question, because i've already thought of 5 answers

Hurkyl

He forgot to say that the line (segments) have to be drawn contiguously; each line segment begins where the previous one ends.

Rogerio

A solution...

Rogerio

I decided to remove the figure cause there is no "spoiler mode" for figures...

For the points below

................
..1...2...3...
................
..4...5...6...
................
..7...8...9...
................

use these lines:

DaveC426913

This is the classic think-outside-the-box puzzle.

Proton Soup

ah, yes, i remember it now. even though i remembered the basic strategy, it still took a few tries in my head to arrive at the result.

The Dagda

Oh yes apologies. It must be a continuous line, ie you're not allowed to lift your pen from the paper.

Well done those who got it, yeah it is a classic but it stumps so many people I rather like it. It's one of those puzzles were people impose rules on themselves.