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How do you draw 4 straight lines with 9 dots?

Drawing 4 straight lines that pass through 9 dots is a fun puzzle that requires some creative thinking. At first glance it may seem impossible, but with the right approach, you can find a solution.

The Puzzle

Here are the specifications for the puzzle:

  • You have 9 dots arranged in a 3×3 square grid
  • You need to draw 4 straight lines that go through all 9 dots
  • The lines cannot cross or go outside the grid

This puzzle became popular in the 1900s and is sometimes called the “9 dots puzzle.” It’s a good brain teaser that requires you to think outside the box.

Why It Seems Impossible

At first glance, this puzzle looks impossible. With 9 dots arranged in a square, your natural tendency is to draw lines inside the square. But you soon realize that there’s no way to draw 4 lines within the square that each connect 3 dots without the lines crossing.

The key is that the puzzle does not say you need to stay within the square. You have to expand your thinking beyond the box created by the 9 dots. This “outside the box” thinking is essential for solving the puzzle.

Thinking Outside the Box

To solve the 9 dots puzzle, you need to draw lines that extend beyond the square formed by the dots. You can think of the dots as forming a 3 by 3 grid, with imaginary rows and columns extending out:

. . .
. . .
. . .

By drawing lines from end to end both vertically and horizontally, you can connect all 9 dots with just 4 straight lines without any line crossings.

Step-by-Step Solution

Here is one way to draw 4 straight lines that go through all 9 dots:

  1. Draw a horizontal line to the right of the grid, connecting the tops of the left column and extending past the right column
  2. Draw a vertical line below the grid, connecting the bottoms of the bottom row and extending past the top row
  3. Draw a horizontal line to the left of the grid, connecting the tops of the right column and extending past the left column
  4. Draw a vertical line above the grid, connecting the tops of the top row and extending past the bottom row

This connects all 9 dots with 4 straight lines that do not intersect or go outside the dots. The key is extending the lines beyond the box formed by the grid of dots.

Visualizing the Solution

It can help to visualize the solution. Here is a step-by-step diagram showing how the lines connect the 9 dots:

9 dots Line 1
Line 2 Line 3
Line 4

As you can see, by extending the lines beyond the square formed by the dots, you can connect all 9 dots with just 4 lines.

Other Solutions

The solution shown above is just one way to solve the 9 dots puzzle. There are a few other possible solutions:

  • Draw the vertical lines first, then the horizontal lines
  • Draw the horizontal lines first, then the vertical lines
  • Connect the dots in a circular pattern rather than straight lines

As long as you draw 4 lines that extend beyond the square formed by the dots, you can come up with a valid solution. The order and exact path of the lines can vary.

Trying It Yourself

The best way to understand the 9 dots puzzle is to try it yourself. Get a piece of paper and make 9 dots in a 3×3 square grid. Then try to draw 4 straight lines that connect all the dots. It will likely take some trial and error before you get it.

Some tips:

  • Do not limit yourself to the square formed by the dots
  • Let the lines extend up, down, left and right as needed
  • Imagine columns and rows extending out from the grid
  • Work systematically and connect all 9 dots

When you finally connect all 9 dots properly with 4 lines, it’s an amazing “aha” moment as you overcome the puzzle’s constraints. Testing different line paths and directions is key.

The Benefits of Solving the Puzzle

While a simple brain teaser, the 9 dots puzzle has some worthwhile benefits:

  • Thinking outside the box: This puzzle exemplifies lateral thinking and overcoming self-imposed constraints.
  • Creativity: You need to come up with an unconventional solution to connect the dots.
  • Problem-solving: It exercises your logical thinking and troubleshooting abilities.
  • Patience: Trial and error are required to figure out a line configuration that works.

The 9 dots puzzle shows that we often need to expand our perspective and not limit ourselves to obvious solutions. Simple yet clever, it’s been intriguing people for over a century.

History of the 9 Dots Puzzle

The 9 dots puzzle has an interesting history. While its exact origins are uncertain, it’s been around for over 100 years:

  • It may have first appeared in magazine puzzle columns in the early 1900s.
  • In 1914, it was referenced in a book of math recreations by Samuel Loyd.
  • It gained prominence when included in creativity and problem-solving texts in the 1930s-1950s.
  • Management consultant W.J.J. Gordon popularized it in the 1960s as a corporate training exercise.

The puzzle became widely known as the “9 dots puzzle” or the “9 points problem.” It exemplified the need for creative thinking to solve problems.

While simple on the surface, the puzzle stumped many people. But with the “aha” moment of drawing lines outside the box, they realized the importance of open-minded thinking. This lesson contributed to its longevity as a teaching tool for problem-solving.

Variations and Related Puzzles

There are many variations of the 9 dots puzzle that provide additional challenges:

  • Use curved lines instead of straight lines – This requires even more outside the box thinking.
  • Connect the dots using just 3 lines – Adds extra difficulty and may have multiple solutions.
  • Use more dots – Puzzles like “connect 12 dots with 5 lines” build on the same concept.
  • Restrict line length – Lines can only be a certain length, adding tricky constraints.

Some related spatial connection puzzles include:

  • The triangles puzzle – Connect several dots to form triangles without overlapping.
  • Flow Free – Connect colored dots while filling a grid.
  • Hashi – Create bridges between dots forming a continuous path.

These puzzles also involve connecting dots, but often with different rules and limitations. But they all require creative strategy in how the connections are made.


The 9 dots puzzle is deceptively simple – connecting 9 dots with 4 straight lines seems easy until you try it. By forcing you to go beyond obvious solutions, it pushes your brain to think more expansively. Mastering the puzzle provides a sense of accomplishment and insight into overcoming unseen barriers.

While invented decades ago, the 9 dots puzzle remains popular today as an engaging brain teaser. It teaches valuable lessons on creativity, constraint-breaking thinking, and perseverance that can apply far beyond the puzzle itself. Whenever you feel stuck on a problem, remember the out of the box insight required to connect the 9 dots, and try looking at it in new ways.