"Accurate to the centimeter!" Li Yun couldn't help but take a deep breath and began to calm down and start measuring.

For the accuracy required by Mo Jiazi for the ruler, he can have a great sense of confidant, the more skilled the craftsman, the higher the requirements for precision.

The difference is not a simple statement, especially for a difficult project such as the construction of arch bridges, which requires extremely high accuracy of measurement, and often a small mistake can cause catastrophic losses. Even if there is a craftsman who has accurately measured it, he still measures it himself to rest assured, which ensures the quality of the arch bridge.

One zhang is equal to ten feet, one foot is equal to ten inches, and one inch is equal to ten, Li Yun was sure again and again, not daring to have a trace of sloppiness, and striving to be extremely accurate.

"One cent equals ten cents!" However, when Li Yun was accurate to the centimeter, he was stunned for a moment, because the Tang Dynasty was divided into large rulers and small rulers, and the standard used by Li Yun was a large ruler, and a point of such a large ruler was only equivalent to about three millimeters to four millimeters in later generations, and such a short distance could not be accurate to ten centimeters at all.

"It's not that simple!" Li Yun sighed in his heart, he knew that the question from Mo Jiazi was not so simple, it was impossible to be accurate to ten centimeters, even if it was forcibly divided, I was afraid that in the end it would destroy this ruler, and I couldn't see the scale clearly.

Zi Mozi said: Medium, the same length. Since there is no way to be accurate to every centimeter, it can be accurate to the fifth centimeter. Li Yun said with a wit, as long as it is accurate to the fifth centimeter, if you need to be more accurate on the scale, you can visually detect the closest length.

When he personally carved the fifth centimeter mark in the middle of each inch, he looked at the precise scales, and his heart suddenly became proud, which was the most accurate ruler he had ever used.

This kind of ruler can be said to be a priceless treasure for the children of the Mo family, with such an accurate ruler, he can accurately measure everything in the world, and there is a feeling in his heart that everything in the world is clear in his heart, and it is all in the size.

"The next and most important step is to make this wooden ruler easy to control with one hand." Li Yun looked at the wooden ruler in front of him, which was much taller than him, and couldn't help but fall into deep thought. Two of the three requirements have been completed, and the rest is the most difficult part, how to make a one-zhang long wooden ruler can be controlled between one hand, Li Yun looked at the one-zhang-long wooden ruler in front of him and fell into deep distress.

Originally, when he held a three-foot-long wooden ruler, he didn't think this homework was too difficult, but when the one-foot-long wooden ruler was placed in front of him, it made him solemn.

To tell the truth, a one-zhang long wooden ruler is very common in practical use, and some large utensils are required to measure such a long wooden ruler, and he didn't feel anything originally, but when he combined Mo Jiazi's requirements, he found out how convenient it was to really make the kind of ruler that Mo Jiazi said.

"How did Mo Jiazi do it!" However, a long time has passed, and Li Yun still has no clue, no matter how hard he thinks about it, he can't figure out how to turn a one-zhang-long ruler into a palm-sized one.

"Young master, in my opinion, it must be the Mo family who is talking nonsense, and he himself admits in public that the distance is immutable, and it is impossible for a ruler to become the size of a palm." The old servant comforted him.

Li Yun shook his head dejectedly and said: "Although the Mo family said that the distance is immutable, we have changed the status quo and changed the distance, those who go around the long road can build bridges and roads, and those who travel far can speed up the carriage and horses, so that the road can be driven in a shorter time." And the intention of coming to Mo Jiazi's question is also like this! ”

The old servant couldn't help but acquiesce, and he didn't know how to comfort Li Yun, after all, since Mo Jiazi gave his apprentice a question, he must have already had a draft in his heart.

However, after a long time, Li Yun still had no clue, according to the knowledge he had learned, there was no way to do it.

"It seems that I am still too pretentious, I originally thought that I could compete with the Mo family, but now it seems that even the apprentices of the Mo family may not be able to win." The more Li Yun thought about it, the more angry he became, and he couldn't help but be furious, and angrily threw the wooden ruler in his hand to the ground.

The wooden ruler was a foot long, made of thin and long wooden boards, and was heavily slammed to the ground, and it was directly broken into several pieces at the moment.

The old servant couldn't help but say with pity: "This is a wooden ruler that the young master has worked so hard to make!" ”

Li Yun spent a lot of effort on this wooden ruler, he saw it in his eyes, and when he saw that the wooden ruler was destroyed, he couldn't help but lean over and pick up the broken wooden ruler on the ground piece by piece.

When the old servant picked up a few pieces, his hands really couldn't take them, and finally he had to stack the wooden rulers in his hands and continue to pick up the remaining broken wooden rulers.

However, the old servant didn't see it, and when Li Yun's originally decadent eyes inadvertently saw the wooden rulers stacked on top of each other, he suddenly rose up, and his eyes suddenly brightened.

"Hahaha, I understand, I finally solved the problem of the Mo family." Li Yun suddenly laughed like a maniac.

"Young Master! What's wrong? The old servant hurriedly got up and looked at the young master in horror as if he was going crazy.

However, Li Yun didn't pay attention to the old servant at all, but directly picked up a piece of wooden ruler that was long and disconnected, and with a snap, he actually broke it again.

Under the worried gaze of the old servant, Li Yun stacked the broken wooden rulers in his hands, only to see that the wooden rulers that were one zhang long were only the width of his palm.

"What does the young master mean by cutting a one-zhang long wooden ruler into small sections?" Only then did the old servant suddenly realize Li Yun's intentions.

Li Yun nodded proudly and said: "Yes, although the ruler is long, it is about five centimeters thick, if I wait to cut the one-zhang long wooden ruler into half a foot long, in this way, it is only one inch wide, only in this way can the one-zhang long ruler be in the palm of my finger." ”

"But in this way, wouldn't it be more troublesome to use such a wooden ruler section by section, and I'm afraid it will no longer be accurate." The old servant shook his head. If when measuring the object, it is necessary to use a piece of wooden ruler to pave it, and after using it, put it away piece by piece, it is very troublesome, and if you inadvertently move a wooden ruler, this length is no longer accurate.

Li Yun laughed and said: "What's so difficult about this, we just need to build a 'bridge' between the two wooden blocks to connect them, connect the two halves of the ruler with rivets, and connect them like chains." ”

Li Yun said, picked up two small pieces of wooden rulers in his hands, pinched the tail with his fingers, and flexibly moved the two halves of the wooden ruler back and forth.

The old servant's eyes lit up suddenly, and he couldn't help but exclaim: "The young master is really talented and smart, and he has solved the problem of the Mo family so easily. ”

Li Yun couldn't help but show a hint of pride, but then sighed: "The craftsmen in the world don't know how many things, they are all used to using a three-foot wooden ruler, only the Mo family is dissatisfied with the three-foot wooden ruler, we all think that the Mo family is picky, and now we know that as long as there is a heart, everything in the world is not difficult."

"As soon as such a wooden ruler comes out, it must be the gospel of craftsmen all over the world, and I asked the young master to name it." The old servant said with a look of relief.

"Since these wooden rulers can be folded into each other, why not call them folding rulers?" Li Yun said in his heart.