Siheyuan: I have a mysterious factory

Xu Dajun traveled to the world of "Love in a Courtyard" and became Xu Damao's younger brother.
With a mysterious factory presented by the system.
Xu Dajun quietly rises in this world.
When others are still relying on the system to grow crops and food, hoard eggs, raise rabbits, kill pigs and sheep, and collect antique calligraphy and paintings everywhere.
But he has already started building tanks, rockets, and warships for the country.
Be one step ahead of other countries and start a technological powerhouse.