- 24 Mar '09 00:45 / 1 edit

Sho nuff. We got that one in the 8th grade. You just have to think outside the box, so to speak.*Originally posted by wolfgang59***Draw nine dots so that they are arranged in a 3x3 square.**

Can you connect all nine dots with 4 STRAIGHT lines without taking pen (or pencil or chalk or other marking-tool) from paper?

Is it possible? - 24 Mar '09 18:12

It's not only possible, I can do it in one line, and one stratight line only. Not that difficult. You really have to think outside the box.*Originally posted by wolfgang59***Draw nine dots so that they are arranged in a 3x3 square.**

Can you connect all nine dots with 4 STRAIGHT lines without taking pen (or pencil or chalk or other marking-tool) from paper?

Is it possible? - 25 Mar '09 06:01

Not at all, I can do it with no difficulty.*Originally posted by Thomaster***one straight line? That's impossible!**

Everytime I present this solution people say "You're cheating!" but I'm not. What they really mean is "You don't do it as it is meant to do!" or "We didn't think of that!".

So there is definitely a solution for 9 dots and one straight line. - 25 Mar '09 13:00 / 1 edit

Well, you can always narrow the definition to the extent that only one solution is possible. But the problem stated as it was from the beginning, in lay terms.*Originally posted by wolfgang59***maybe I should have said 9 points rather than dots? and defined point, and line and straight.**

In fact I never really defined "9" did I?

Put the nine points slighle tilted, roll the paper to a cylindre, and then draw the line around the cylender, hitting three points every turn.

That's *one* solution, but I assumed that the paper should be finite in size and flat. So my solution is 9 points on a flat paper. You can use a ruler to make the line perfectly straight.

Why use four lines when one is enough? - 25 Mar '09 14:12

Your cilinder trick doesn't work, since the line should remain straight. (what is impoosible on a rolled paper)*Originally posted by FabianFnas***Well, you can always narrow the definition to the extent that only one solution is possible. But the problem stated as it was from the beginning, in lay terms.**

Put the nine points slighle tilted, roll the paper to a cylindre, and then draw the line around the cylender, hitting three points every turn.

That's *one* solution, but I assumed that the pa ...[text shortened]... can use a ruler to make the line perfectly straight.

Why use four lines when one is enough?

I think I understand how you do it with one line. You take two papers.

First you hit three dots with a straight line and you 'park' the line in the second paper. You can simply move the dots :-)