For years I’ve been toying with two metaphors for Olivia Tremor Control’s beguiling, befuddling, bewildering album, Black Foliage: Animation Music Vol. 1. First, a garden: Its mix of brightly melodic, supremely catchy pop songs and unruly sonic experiments sounds like colorful flowers blooming in a bed overgrown with weeds, dead leaves, spider webs, suspicious mushrooms, a menagerie of creepy-crawlies, black foliage. It’s fitting and evocative, but perhaps too tidy. Listening closer on the eve of the album’s 20th anniversary, I find as much beauty in the weeds as in the blossoms. Those odd interstitials, mixing musique concrete with drones, distortion, and warped instrumentation, are just as cultivated as the more traditional songs, and there is as much joy to be found in the springy percussion of “Black Foliage (Animation 3)” as in the stacked harmonies and majestic arc of “I Have Been Floated.” What I always mistook for rot is actually its opposite.

My second metaphor: a dream. You can see an enormous set of eyes on the wall in front of you, or you might converse in depth with a figure made of jelly, and you only question the logic of such happenings when you wake up — that is, if you remember anything at all in the morning. In the dream, you accept such goings-on as perfectly normal; even if you don’t understand the logic, you understand the lack of logic as a king of logic. Black Foliage seemingly rejects the traditional logic of pop music for something much harder to grasp. Gone are verses and choruses, bridges and solos. There are no pauses between these 27 tracks, no fadeouts and fadeins (except, of course, on the four-sided vinyl edition). Everything melts together; there is always music in the air.

This idea persisted long after I’d given up on the whole garden thing, mainly because there’s a lot to back it up. In the liner notes for Olivia Tremor Control’s 1996 album, Music From The Unrealized Film Script: Dusk At Cubist Castle, the band asked fans to send in recordings of themselves describing their dreams. The results ended up on “Combinations 2″ and “Hilltop Procession (Momentum Gaining),” albeit heavily excerpted, distorted, chopped, and screwed. Moreover, the lyrics suggest you are in a dream state while you’re listening: “Things come rushing in, things come rushing out,” goes “A Sleepy Company,” “when you’re in a dream.”

Have we woken from that dream yet? Two decades after the album made Olivia Tremor Control one of the most popular bands out of Athens, Georgia, Black Foliage remains reluctant to relinquish its mysteries. It sounds every bit as strange and as slippery and as dreamlike as ever, although that whole dream idea suggests a group of musicians defaulting on their artistic decisions, leaving things up to happenstance and exerting no control over the music. I’m reluctant to deny artists credit for their labor, for the hard work that goes into devising a particular sound and then realizing it in the studio, which means there must be a set of rules governing these tracks. The fact that we’re still figuring them out doesn’t mean they’re not there. It just means that this strange and singular album continues to dispel easy interpretations and simple metaphors.

Black Foliage is unlike any other album, but that doesn’t mean it isn’t without context. Olivia Tremor Control were a flagship Elephant 6 band, with roots that extend well beyond the Athens city limits. It starts in Ruston, Louisiana, population: a few thousand people, where Will Cullen Hart, Bill Doss, Robert Schneider, and Jeff Mangum met and started playing around with four-track recorders, exchanging weird-ass recordings. As adults they migrated to Denver and finally to Athens, Georgia, along the way establishing Elephant 6 as a loose, grassroots thingamabob: part record label, part philosophical collective, like Dogme 95 but with musical instruments and people you’d want to talk to at parties. Eventually this musical amoeba migrated to Georgia, where the quartet continued making weird music and eventually released a handful of 7″ singles at a time when releasing vinyl was almost unheard of. Membership was liquid, with musicians popping when needed and available. Schneider and Mangum focused more on Apples In Stereo and Neutral Milk Hotel, respectively, so the band cohered around Hart and Doss as its guides.

Their love of ’60s pop wasn’t exactly unusual in the waning days of the 20th century. In the mid 1990s the early internet made trading bootlegs much easier, and one of the most popular was Smile, the notorious lost album by the Beach Boys. Groups like the High Llamas, the Divine Comedy, Cardinal (and Eric Matthews solo), and even Belle & Sebastian were exploring the lush harmonies of ’60s pop, delving deeper than the Beatles and the Stones to find some sounds and ideas that jostled against the prevailing alt-rock rules of the era. Elephant 6 was the Southern nexus for this loose movement, and all of the bands under that umbrella tinkered with those influences. But few did as much with them as Olivia Tremor Control, who re-situated ’60s pop so that the familiar suddenly sounded fresh and fantastical.

Black Foliage thrives on the contrast between rigidly constructed pop music and loosely structured experiments, between logic and intuition. Pop is controlled; noise is uncontrolled. Rather than a simple binary, however, the contrast between these two musical poles creates a static/signal ratio that is always shifting, even right now. I forget how focused and succinct the 23-second “Opening” is. It melts into “A Peculiar Noise Called ‘Train Detector,'” the first “pop” tune on the album and one that introduces many of the ideas the musicians will be exploring. But that song is just as noisy, just as unhinged as any of the musique concrète interstitials that follow. That only difference is the din is given shape by the vocal melodies. There is, ultimately, no distinction between “music” and “noise.” There is only sound.

Joyous sound, it should be noted. Even at its darkest, there is still a bubbly kind of optimism coursing through Black Foliage, as Hart and Doss sing about endless permutations of best selves, a slipperiness of identity that is empowering rather than obscuring. Perhaps the most focused set of lyrics on this album, “The Sylvan Screen” opens with someone at their window, watching the cars pass by on the street below. “No one sees me looking at them from my window, and I can be any one of them I wanna be.” The music imitates the back and forth of traffic, each instrument passing into and then out of the song: the creaking floorboards, the lo-fi guitar strum, the disembodied saxophone, the ectoplasmic banjo, the barely corporeal electric guitar. The song sounds like it might veer off in any direction or indulge any tangent at any moment, but the band manage to keep it on track, a feat that becomes increasingly impressive the deeper into the song they get.

Failed metaphors aside, what I’ve decided is that Black Foliage is something much more basic and much more complicated. It is a celebration of sound, an explication of the metaphysics of music, a treatise on the pleasures of hearing. A party, perhaps. “Above the clouds and below the bark they’re having parties,” they sing on closer “Hilltop Procession (Momentum Gaining).” In fact, it sounds like they’ve invited the entire population of Athens to sing along. “Beyond those roots find a treehouse symphony there.” Black Foliage is Olivia Tremor Control’s earnest invitation for all who hear these notes to join the revelry.