Built jokes

I've patched 1,000 roofs, and they don't call you Boris the roof patcher. I've built 100,000 swords and shields, and they don't call you Boris the blacksmith, but you fuck one goat!

Why is it called a building if it's already built?

Why did Trump decide to build the wall?

Because China built a wall and they do not have any Mexicans.

When China built the Great Wall, the Mongols invaded them and founded the Yuan dynasty. With Trump building his wall, will the Mexicans invade the US and found the Juan dynasty?