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This is 99% Invisible. I'm Roman Mars.

How to make a concrete stylus. Take a large nail.

Heat the tip red hot in a blue gas flame. Drop it in ice water.

Now it will resist abrasion as it cuts through the sand, cement, and rock particles in concrete not yet hardened.

From the abstract to the concrete. Signed. A friend.

I first found Nico by staring at the sidewalks. Delphine Visual is a journalist from San Francisco.

One of my favorite things was always to get lost in San Francisco and stare at things that I normally might have looked past.

And then I saw his name written in the sidewalk.

And I thought it was interesting. And then a block later I found his name again.

I turned a corner through Chinatown into North Beach and I found another one.

You know, I would find them not just in North Beach but Chinatown, Russian Hill, Telegraph Hill.

They would be references to the street name.

Nico on Thulver. Nico on Night. Nico downtown.

And then the personality of me was really coy. It was like Nico was here. Nico gets it all. Nico concrete compulsive.

And I remember once I was just saying to myself, damn Nico is everywhere. And then I looked down and it said Nico is everywhere.

I felt like a duty. And I remember thinking that I've this is my duty to write this story.

And then coincidentally I'd run across a clue that said Nico on duty.

So Delphine decided to track Nico down. You know, I wanted to know was this guy alive. Why did he do it?

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