This is 99% Invisible.

I'm Roman Mars.

Tim Hartford is a master at picking out the perfect little story that explains some huge

economic principle.

In his long-running Financial Times column called The Undercover Economist and in his books

and in his radio shows, he's been my go-to guy for learning about the economics and math

behind the world at large.

His latest radio series for the BBC is called 50 Things That Made the Modern Economy,

and with this project, Tim has made a podcast almost perfectly crafted to light up the pleasure

centers of my nerd brain.

After he produced 50 fascinating stories about 50 everyday objects, he decided to come

back for another season that premiered last month with another 50 mini-documentaries

of inventions that are so basic but so fundamental to how we live.

We have three of the 50 things on our show today, Radar, which I'm sure you know about,

but you have no idea how fascinating its origins actually are.

The S-Bend, the crucial innovation in pipes that made indoor plumbing possible in bricks.

You know what bricks are, bricks are cool.

You're in for a treat.

Up first, the story of Radar.

In Kenya's Rift Valley, Samson Kamau sat at home, wandering when he'd be able to get

back to work.

He should have been in a greenhouse on the shores of Lake Nivasha as usual, packing roses

...