[Have you read this book yet? If not, why not? I'm only on p. 100 but wanted to share this part that made me cry..]

An ambulance drove down the street between us, and I imagined who it was carrying and what had happened to him. Did he break an ankle attempting a hard trick on his skateboard? Or maybe he was dying from third-degree burns on 90% of his body? Was there any chance I knew him? Did anyone see the ambulance and wonder if it was me inside?

What about a device that knew everyone you knew? So when an ambulance went down the street, a big sign on the roof could flash

DON'T WORRY! DON'T WORRY!

if the sick person's device didn't detect the device of someone he knew nearby. And if the device did detect the device of seomone he knew, the ambulance could flash the name of the person in the ambulance and either

IT'S NOTHING MAJOR! IT'S NOTHING MAJOR

or, if it was something major,

IT'S MAJOR! IT'S MAJOR!

And maybe you could rate the people you knew by how much you loved them, so if the device of the person in the ambulance detected the device of the person he loved the most, or the person who loved him the most, and the person in the ambulance was really badly hurt, and might even die, the ambulance could flash

GOODBYE! I LOVE YOU! GOODBYE! I LOVE YOU!

One thing that's nice to think about is someone who was the first person on lots of people's lists so that when he was dying, and his ambulance went down the streets to the hospital, the whole time it would flasy

GOODBYE! I LOVE YOU! GOODBYE! I LOVE YOU!

- From Extremely Loud & Incredibly Close, p. 73
Jonathan Safran Foer, who also wrote Everything is Illuminated