“How to explain a Brunelleschi?” says Avio. 

“How to explain how Brunelleschi build his Duomo in Florence? 

It is like a man in the year 1900 saying, ‘I will take you to the moon.’”

“How?” you ask. 

“By building a spaceship.”

“How?”

“By building rockets.”

“What fuel will the rockets use?”

“I will find a fuel.”

“How will you navigate the spaceship?”

“I will point it at the sky and work out a way.”

“How will it land on the moon?”

“Slowly.”

“But how?”

“I will solve that when we get there.”

“And how will you get back?”

“The same way we got there.”

“And landing?”

“Let us wait for that wonderful moment to arrive before we solve it.”

“This is how Brunelleschi build his Duomo.”