Brain Teaser: 

Ask someone if they can connect all nine dots arranged in a square grid with four straight lines without their pen leaving the paper.

The Secret: 

You literally have to think “outside of the box” to solve this mystery. The rumor is that the phrase “outside the box” derives from this puzzle. Simply draw a line as in Figure 1.
This is one that I learned in the fourth grade. In fact I spent the happiest three years of my life in the fourth grade. I didn’t want to move on to the fifth grade because I didn’t want to pass my father. Dad was also my ride to school.