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Have you ever felt like lots of songs sound really similar, even when they're by completely different artists? You can't really put your finger on what they're doing that sounds so

familiar, but you know it's something. It turns out there are certain elements that show up

again and again in popular music.

Rhythms, like the Four on the Floor drumbeat, have been used in dance music since the disco years.

There are also formulas for song structure, like the tried and true format that goes like this, verse, chorus, verse, chorus, bridge, chorus. The chords of a song

can also follow familiar patterns. It doesn't matter if the songwriter has a master's degree in

music theory, or if they've never taken a music class in their life. It doesn't really even

matter what genre they're in. The same chord changes get used all over the place.

They're almost like foolproof recipes for writing catchy hits. You've probably heard dozens

of these songs without realizing what they all had in common. But the recipes have been there all along.

A big part of what makes a song feel a certain way comes from the chord changes, or the chord

progression. A chord progression tells you which chords are being played, and in what order. When two

songs use the same progression, it means they share the same basic musical DNA, even if the

style is totally different. One of the most popular chord progressions

is over 300 years old, and it's still going strong. It was written by a composer named

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