The progress of technology is always driven by demand.

Just like Li Yuanjia's memory, there was a period of time when AMD was very weak, and the performance of the CPU was far from that of its competitors, so Inter had no motivation to put the latest technology into production. Anyway, from the second generation to the seventh generation, almost every generation has only improved a little, just like squeezing toothpaste, squeezing out only a little bit at a time, and finally being named the "toothpaste factory".

Later, AMD tried its courage and launched a new architecture CPU, and when the performance caught up with the new Core products, Inter could only take out the technology it had accumulated and released the eighth generation of products with greatly improved performance......

This example may be a bit inappropriate, but Li Yuanjia feels that Datang's four-wheeled carriage is a product that is "not in demand".

At least for now, there is not much demand.

There are many factors restricting the use of four-wheeled carriages in Datang, such as the relatively high cost at present, the serious lack of senior carpenters, etc., but the most important thing in Li Yuanjia's eyes is undoubtedly the road under his feet!

The road requirements for a four-wheeled carriage are much higher than those for a two-wheeled carriage.

The reason is simple at a glance, the volume of the four-wheeled carriage is larger, because the purpose of adding a pair of wheels is to increase the space of the carriage, so that it can be more comfortable. However, this result also greatly increased the weight of the carriage itself, which caused great pressure on the road surface!

To put it simply, it's a bit like the big trucks that will be overloaded on the road in the future.

Different roads have different bearing capacity for the weight of "trucks", for example, on the road with a weight limit of 50 tons, you run a bunch of large trucks with a load of 100 tons every day, and sooner or later you will not be able to bear it.

In the Zhenguan period, the same is true.

Even in Chang'an City, not all of them are paved with stones, and many of the roads in or in the square are the most primitive dirt roads, but they are relatively strong. It's okay to walk on this road once in a while, but if there are countless four-wheeled carriages running on it every day, I'm afraid it will be over quickly.

This is still inside Chang'an City, and the quality of those official roads outside the city will only be worse!

For example, the road that Li Yuanjia and they are walking on now, because it is the road to Xianling, the construction is naturally much stronger than the ordinary official road, but after a night of rain and snow, it is impossible to see it at this time. Anyway, Li Yuanjia walked on it in a four-wheeled carriage, squeaking much slower than yesterday.

In addition to the weight, there is also the width.

The volume of the four-wheeled carriage has skyrocketed, and the width of the road has also been higher, and the common kind of path is not usable at all. And even if it is the best quality official road, it is troublesome to accommodate two four-wheeled carriages in parallel, or to know how to drive.

So the four-wheeled carriage is not practical at all these days.

That is, a big man like Lu Guogong, one doesn't care about the hundreds of runs, and the other has seen the emperor and Li Yuanjia sitting so comfortably, so naturally he can't bear his two-wheeled carriage......

"But...... One thing is fine. ”

Lowering the curtain, Li Yuanjia leaned back again, and secretly pondered in his heart: "Although this road is not very good, the pressure on me now is small, and there is no problem with running once or twice once in a while...... Ouch! What's going on? ”

The carriage under the buttocks suddenly tossed, and Li Yuanjia hit his head on the wall of the compartment next to him, and couldn't help but scream in pain.

After hearing his voice, a small servant waiting next to him hurriedly said: "The king forgives me, it just rained and snowed last night, and the road is very muddy and ......."

"Alright, no more ado, keep going!"

As soon as he heard it, he knew what was going on, and Li Yuanjia didn't wait for him to finish speaking, so he directly gave the order. It's just that when the carriage continued to move forward, he smiled bitterly in his heart: "I was thinking about the four-wheeled carriage just now...... On this road, you want to promote four-wheeled carriages? Hehe, it's too much to think about! ”

In a depressed mood, Li Yuanjia couldn't help but open the curtain again.

"This is the road to Xianling, and the road surface is already the best grade, right?"

After taking a closer look at the mud next to the wheels, Li Yuanjia pondered for a moment, took a deep breath and said, "In this case, set a big goal for yourself first, build a cement road from Chang'an to Luoyang in this life......"

……

As a "filial son", on the morning of the first day of the thirteenth year of Zhenguan, Li Shimin took a large group of people to spend time in Xianling. After expressing his longing for the emperor, Li Shimin also issued an edict to pardon Sanyuan County and punish the crimes, that is, to exempt them from capital crimes; And the old people over 80 years old in Sanyuan County were rewarded with different property according to their age.

Anyway, at the end of the day, Li Yuanjia was also a little tired.

When he returned to his residence, it was already dark, Li Yuanjia drank a bowl of soup, ate two cakes, and then washed hastily and rested.

Compared with him, Fang Xuanling is actually more tired.

Because after returning to the station, he was called by the emperor along with several other important ministers. Because of a sudden emergency report, several people got together to discuss for a long time, and finally Liang Guogong dragged his tired body back to the small courtyard where he lived.

By this time, it was almost completely dark.

So as soon as he returned to the place where he lived, Fang Xuanling washed his hands with hot water first, wiped his face, and the old servant next to him asked, "Xianggong, do you want to eat now?" In the evening, the king sent a small pot of mutton soup, which was heating on the fire...... In this kind of weather, drink a bowl of mutton soup to warm up. ”

"The king? King Han? ”

"Yes."

"Well, bring it up."

After being stunned for a moment, Fang Xuanling waved his hand, and the expression on his face changed slightly.

Although there was a little bit of an accident, Fang Xuanling was relieved when he thought that Li Yuanjia had often sent things to him. Speaking of this son-in-law, to be honest, Fang Xuanling is not dissatisfied, his status is high, and his personality is good, except that he always likes to do something craftsman, he really can't find anything wrong.

And listening to what her daughter said when she came back, King Han also loved her very much, and she was simply the perfect son-in-law.

Just when the old servant was about to go out, Fang Xuanling suddenly remembered something and hurriedly asked, "Fang Zhong, where is the bereaved love now?" ”

"This ......"

After hesitating for a moment, the old servant bowed and said: "If you go back to Xianggong, Erlang will ask a few friends to play cards together after he comes back, and he should be in his house at this time." ”

"Well, playing cards again?"

After listening to the old servant's words, Fang Xuanling's brows suddenly wrinkled.

"Xianggong, do you want to call Erlang over?"

"No need, go ahead."

After a little hesitation, Fang Xuanling shook his head and asked the old servant to serve the sheep soup.

After the old servant went out, the old man sat down in a small room, and suddenly felt a little uncomfortable—how comfortable would it be if there was a chair with a thick cushion on top of it?

"Some of the things made by King Han are still very good."

A thought suddenly flashed in his mind, which made Fang Xuanling slightly stunned, and then laughed dumbly: "But that card is too easy to indulge in, and those Tianzhu numbers on it are too unorthodox...... Hey? ”