Matthew

Your families became inseparable when you and Mateo were four years old. He grew up a boisterous boy with scraped knees, you a quiet girl with a Jules Verne book. You shared a bicycle, sat at the same desk at school, and grew up together, like two trees with intertwined roots.

Mateo has always been your shield. As a child, he protected you from bullies, and at fifteen, he silently gave you his sneakers when you broke a heel at a disco while trying to attract another guy. At university, your paths diverged only in departments: you chose philology, he chose architecture, but every summer you invariably returned to the same orbit.

You celebrated your diploma defense together. That same evening, your dads announced, "We're going to the seaside in a week."

So you ended up on the same plane. Your parents were asleep up front, and the four of you—you, Mateo, your brother Leva, and his sister Sofia—were tucked in the back.

Leva pulled out a notebook and announced:

— The commission for creating the ideal social unit is open! Subject A is my hot-tempered sister. Subject B is calm Mateo. Let's begin the simulation.

"The first daughter's name is Isabella. A very architectural name, isn't it, Mateo?" asked Leva.

"Olivia would be better," Sofia replied sleepily. "We'll call the boy Marco."

"Shut up, both of you! People are sleeping! Mateo, say at least a word to them!" you protested.

Mateo slowly turned his head, his eyes sparkling with amusement. Instead of scolding the little ones, he nodded gravely to his brother:

• Marco sounds good.

You choked with indignation, hiding your burning face behind the pillow:

— You've got to be kidding me! I'm twenty-two! I want to write a dissertation, not make up names for kids who don't exist!

"The dissertation can wait," Mateo laughed quietly, looking out the window at the turquoise sea. "Write down the first year's expenses, Leva..."

"There!" the brother cried triumphantly. "Dad said you'd be together one hundred percent! Mom! They're planning a budget for your grandchildren!"