In visual art, it's called a triptych -- a piece divided into three connected sections or panels. The individual panels could, in theory, stand on their own, but each adds meaning and significance to the other two, creating a single work that is more than the sum of its parts.
We don't have a name for this concept in music, but we should, especially in the new digital landscape, dominated as it is by singles rather than albums. Three songs is the smallest unit of musical arc, of emotional progression, the midpoint between the song and the album. Two songs only creates a straight line from point A to point B; three allows for a curve, for a complete musical thought.
With that said, here are five great rock triptychs. If we missed your favorite, leave it in the comments.
The Beatles: "Sgt. Pepper's Lonely Hearts Club Band," "With a Little Help From My Friends," and "Lucy in the Sky With Diamonds" (Sgt. Pepper's Lonely Hearts Club Band, 1967)
If you had listened to this for the first time in 1967 (and maybe you did), the crowd noise in the opening seconds of "Sgt. Pepper's Lonely Hearts Club Band" would have tipped you off that the Beatles were up to something new, something bold. As the song nears its end and Sir Paul introduces Billy Shears (a.k.a. Ringo), something funny happens -- "With a Little Help from My Friends" emerges not from the customary silence between tracks, but in one fluid motion from the song before it.
Although this technique may be common now, at the time it was essentially revolutionary -- multiple songs could really be part of one larger thought, despite being listed separately. Conceptually, this was a leap.
Moving forward, the Beatles lead us on a continuous journey, rather than hopping from track to track. In "With a Little Help from My Friends," for example, the line "I get high with a little help from my friends" seems a bit odd in what is otherwise a sugar-sweet song, but it works as foreshadowing for the alternate universe ahead in "Lucy in the Sky with Diamonds."
When "Lucy" ends, we find ourselves firmly entrenched in the Beatles' dream world, which is the profound achievement of this triptych -- it begins by asking us to suspend our disbelief and enjoy a fictional band and ends with us down Sgt. Pepper's rabbit hole.
Mutemath: "Stare at the Sun," "Obsolete," "Break the Same" (Mutemath, 2006)
In some ways, the musical landscape of the '00s mirrored that of the world before Sgt. Pepper, but for different reasons. In the 2000s, after years of album-focused approaches to rock music in the post-Sgt. Pepper's era, the switch from records and tapes to MP3s and the ubiquitous "Shuffle" feature reestablished the old divide between songs, and re-emphasized the supremacy of the single (as we write this, in fact, Spotify interrupts the flow between two songs with an ad for Coke). These three Mutemath tracks, however, demand to be listened to in sequence, without interruption.
"Stare at the Sun" meanders through spacey synth and guitar sounds, building a relaxed mood before heading into an extended coda that introduces a new bass line. That bass line drives forward into the next tune, "Obsolete," a mostly instrumental extension of "Stare at the Sun" in which the band explores all of the harmonies and vibes implied in the latter.
In its final seconds, "Obsolete" powers up again with a sound like rockets firing for take-off, culminating in the first notes of "Break the Same," a nearly six-minute rumination on intolerance that brings the latent energy of the previous two songs to a fever pitch before slowly unwinding into a gentle synth landscape, the eerily calm plane in the aftermath of a tornado.
Altogether, the three songs last over 14 minutes, but feel like one unified musical idea.