Seven days is not a long time, but it is not a short time.

When a new day dawns, the arena is once again bustling with activity.

Standing in the arena and looking at the only two of them, Douglas and Rael, Green knew that it seemed that only the three of them had completed the task. After all, this is a difficult problem that has plagued the Vikings for a long time, and now it takes seven days to solve, which can definitely be called a great test.

As the voice of the narrator sounded again, it was time for the second competition to unravel the mystery, but this time the competition was a little more professional, and Princess Victoria invited the most famous architect and sculptor of the Kingdom of Navia, Master Bartholdi, as the judge of the competition.

It had been a long time since the old Bartodil had participated in such an event since he had been hired by the king as the royal architect, and it was time for him to live out his old age in peace. But this time, in order to be able to check the elf's lovely Princess Victoria, he is still willing to come out for activities.

Every time he stood on the site of the Colosseum of Percel, looking at this huge gladiatorial arena built on an entire mountain, Bartodil could feel the surging in his heart.

He was also one of the builders, and he was involved with his teachers.

And now he's here again with his most proud student, Eliel Shanin.

With Elier's help, Bartodil came to the first house of inspection, which had been built by Rael, the son of Yar of Thor.

The house is small, similar in appearance to the traditional Viking architecture, except that it is made of swarthy wood.

Bartodil looked around the house, and instead of immediately asking people to come forward to test its fireproof ability and sturdiness, he turned to Ariel beside him and asked, "Can you tell what kind of wood this is?"

Ariel stepped forward and tapped it with his hand, then thought about it with a frown, and then said, "Teacher, this can't be the kind of ironwood that grows in the dark abyss you said, right?"

Bartodil smiled and nodded without speaking, but walked straight towards the next house.

Behind him, the guards had already picked up hammers and fuel and began to inspect the house, and then the Viking audience saw the magic.

When the hammer slammed into the house, the wood not only did not break, but sounded like the clashing of gold and iron. Then, when the fuel was spilled on it, the wood not only did not burn, but smoked and went out.

The Vikings who were watching immediately clamoured: if they all built their houses out of wood like this, why should they worry about being destroyed by dragons?

At this moment Bartodil had already walked to the front of the second house, which was built by Douglas, the son of Yar of the Isle of War.

The appearance of the house is nothing special, it is square, with a flat roof, and from the outside it looks like it is made of stones, but it is clearly not that simple.

Bartodil stepped forward, stretched out his finger and touched the wall that was not yet dry, then put it in front of his nose and sniffed it, and then said to Ariel beside him, "Come on, I'll test you again! What materials are used in this house?"

Ariel nodded, sniffed it like a teacher, thought for a moment, and said, "There is a cloud of lime..."

"What else?"

"Volcanic ash?" said Eliel, somewhat uncertain.

"Haha, you're not mistaken. Bartodil laughed heartily when he heard Aryl's answer.

"But, teacher, can volcanic ash make a house?" asked Ariel in surprise.

"This was a long time ago! When the Pelcelluel Arena was built, I heard from my teacher that the ancestors had also considered this method of combining marble lime with volcanic ash, but then because of the ..... Hey, what kind of material is this made of?" said Bartodil, who had already walked to the third type of house, suddenly stopped and looked at the house in front of him in surprise.

From the outside, it looks like the second house, with a square flat roof and dark gray walls, but this one is clearly more condensed, its walls are so hard that they don't feel wet and dry, and the wooden pillars used to support the roof have been removed.

"How long did it take them to build this house?" asked Bartodil, who had been on guard when the house was built, immediately turning to the captain of the guard behind him.

"Four days, I guess," said the captain of the guard, after a moment's thought, "they built it in a similar way to Douglas's, except that their house curdled faster, and then it was just watered. ”

"Later, when they removed the planks, I sent someone to check it, and it was really magical!"

......

It was Green's first time on the Colosseum's commentary platform, which was located on a bulge in front of the King's Stage. On the left is the Seat of Nobles, where the Yar and nobles of the tribes are seated, and on the right is the Seat of Honor, where Viking witches from the temples of the islands are seated.

At the moment, all three people involved in the second round are standing here, waiting for the final judgment of Master Bartodil. The gray-haired old Viking man over half a hundred years old walked to the horn with a trembling cane, then coughed and spoke hoarsely.

"I just looked at it, and the houses that the three of them built are sturdy and have some fire resistance. As Master Bartodil spoke, the Viking audience fell silent.

"According to the rules, all three of them can be regarded as passing!"

Before the Viking audience had time to cheer, Bartodil suddenly changed his tone and said, "However, in terms of practicality, ......"

"I'm not targeting anyone, I'm saying that except for the house built by this little locksmith Green, everything else is rubbish!"

......

Lasting silence.

No one expected that in the end, Master Bartodil would give such a comment.

Green lowered his head and touched his nose a little speechlessly, looking at the thin Viking old man in front of him, just now he was a little worried about whether this master would fall in the wind, but he didn't expect him to say such domineering words in a blink of an eye.

Isn't this just pushing yourself to the fire and roasting?

Sure enough, the little thunder god Rael on the side first glared at Green fiercely, and then said angrily, "Even if ours is not as good as his, it can't be said that ours are all rubbish!" He can accept defeat, but he must not accept such an insult.

Bartodil straightened up slightly and glanced at Rael, then said to the giant horn, "None of you here may know what the black wooden house is made of! ”

"First of all, they only grow in the Dark Abyss, and their names are Ironwood. ”

"Oh my God! no, isn't it? under that huge crack!"

"The cliffs are very steep, how did they get this timber up?"

"It's dangerous!"

......

Hearing the master's explanation, the Viking audience immediately exclaimed, because the horror story about the dark abyss could not be told for days and nights.

It was an island of death, and the entire island was dark and hard rock, devoid of any vegetation. In the middle of the island lies a large deep canyon crack that splits the island in two like a scar. There are so many dragons that look like blades that they whizz past you, and even if you're covered in iron armor, you'll be cut into a pile of mud.

Normally, no Vikings would want to set foot on this island, let alone see if there are any trees growing beneath the Dark Abyss.

"Secondly, ironwood is also very heavy and hard, comparable to steel, so it is not easy to cut down. If you have to cut them, you can only burn them with fire little by little, and then use an axe to cut them on the burned marks, and as for how long you can cut them, it depends on how long you can live. ”

Hearing Bartodil's explanation of the wood so clearly, Relton was speechless, for he did not know the growth habits of the wood. He had only salvaged some of these timbers at an outlet to the sea on Dark Abyss Island.

"Let's talk about the second house, then!"

Hearing the master talk about himself, Douglas shrugged his shoulders indifferently, he only cared about whether he passed the test or not, and the ranking was only in the last game that mattered.

"The house was watered with a mud mixture of volcanic ash, marble lime (quicklime), sand, stones. Although they are common, they have a fatal drawback, the solidification cycle can be as long as several months, and they cannot encounter particularly cold weather, otherwise they will crack, so this is not realistic for us Vikings. ”

"Now let's talk about the third kind of house, which is made of a material called cement, which I just asked Green. ”

"It's also very common, and it's made when marble and clay are mixed together and burned at high temperatures to produce this cement. They are then ground into powder, mixed with sand and stones, and can be used to build houses. ”

"After the house is built, it is comparable to a castle made of huge stones, there is no need to worry about being destroyed by dragons, and there is no need to worry about burning in case of fire, and it has a very short solidification period, so you don't have to wait long to decorate and move in. ”

"Really? And such amazing material?"

The Vikings immediately exclaimed.

"Master, do you know how this cement is produced?" and a clever Viking had already shouted.

"Green, do you have any cement left? I'm going to buy it! Buy ten ships!"

"I want to buy twenty ships too!"

The lower floors of the Colosseum were mostly occupied by wealthy Viking merchants, who had apparently seen the great potential of the cement.

"Hehe, I don't know these questions, I just gave them a brief explanation from a professional point of view, if you want to purchase this kind of cement or buy a formula, you can consult our cement inventor, Green. ”

......