Roman Mars’ podcast 99% Invisible covers design questions large and small, from his fascination with rebar to the history of slot machines to the great Los Angeles Red Car conspiracy. Here at the Eye, we cross-post new episodes and host excerpts from the 99% Invisible blog, which offers complementary visuals for each episode.

This week's edition—about song design—can be played below. Or keep reading to learn more.

A song is a product of design. It’s difficult to create an original melody, but that’s only the blueprint. Every element of a piece of music could be produced any number of ways, depending on which instrument plays at what time, for how long, and with what kind of effect.

The architecture behind a piece of music can be much more involved than meets the ear, and this is what inspired Hrishikesh Hirway to start a podcast called Song Exploder, where musicians “take apart their songs, and piece by piece, tell the story of how they were made.”

This week, we’re featuring Hrishikesh’s Song Exploder episode about the main title theme to the Netflix original series House of Cards, by composer Jeff Beal.

Hrishikesh spoke with Beal about his collaborative process with executive producer David Fincher, how they found the mood and musical palette for the show and its theme, and how the score changed from Season 1 to Season 2.

The Season 1 theme has sweeping violins:

The Season 2 theme loses the violins in favor of a full cello assault, making the mood darker:

To learn more, check out the 99% Invisible post or listen to the show.