# Puzzle time: think outside the box

I'm not a big puzzle person but I ran across this puzzle twice in less than a week.  Once in a project management book and once in an architecture book.  I'm sure many of you have seen it before.  If not, have fun.

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1. Ishan says:

lets label the dots

1 2 3

4 5 6

7 8 9

-So draw a line from 1 to 9 (diagonally going through 5).

-Then draw a line from 9 to 3(vertically going through 6), but dont stop at 6, keep moving until you reach the lenght of an imaginary dot above 3

-Now draw a line from that imaginary dot to an imaginary dot beside 7 (diagonally going through 2 and 4).

-Finish off with a line from the 2nd imaginary dot to 9 (horizontally going through 7 and 8 )

2. Wow… this is an old favorite of mine… so much, that even our company (http://www.response.hu) and key product logos are based on the nine dots here!

3. Yeah, Ishan you are spot on. But, can you do it with only three line?

4. craigrow says:

5. Clint says:

Using Ishan’s diagram, in one continuous stroke do: 2 5 8 7 4 1 4 7 8 9 6 3

6. Richard McNally says:

If you imagine that this problem has been printed out and given to you on a sheet of paper then its actually possible to do it with a single straight line. Just fold the paper into a cylinder and go around it. I guess that you could do the same with a monitor as well.

Another way of using just one line is to make that line so thick that it touches all three points on the line.

You can also have use a single line if your willing to do some folding and cutting of the paper.