"Have you ever heard that it's impossible to fold a piece of paper more than seven times? Actually, it is just a popular myth.
The myth refers to folding a piece of paper in half many times in any direction. The paper is folded in half. Try it for yourself with a piece of notebook paper. ____ But when you make the fifth and sixth folds, you'll notice that it's increasingly hard to fold the paper. Why does it happen? Because the number of the layers (层) of paper doubles with each fold. For example, after the sixth fold, you're left with 64 layers of paper. If you have strong hands, you may be able to make that seventh fold. If you start with a piece of paper that is 0.01 centimeters thick, it'll be as thick as a notebook after seven folds. And it would seem impossible to make more folds. At this point, you may be thinking that the paper-folding myth doesn't sound much like a myth.
However, in 2002, a high school student named Britney Gallivan proved the idea wrong. Britney successfully folded a 1.20-meter-long roll of toilet paper 12 times (note that she used single-direction folding). She also developed a math rule. This is convenient. It allows you to find out the maximum (最大的) number of possible folds based on paper thickness, paper length, and direction of folding.
Since Britney's success, many people have managed to fold a single piece of paper more than 7 times. Students even folded a piece of toilet paper a total of thirteen times. The toilet paper they used was about 4,000 meters long!