As glass marbles glide along the four separate tracks of Loop—the third and latest project by Snarkitecture for clothing brand COS—the mechanics seem so simple. Nothing but kinetic energy propels the balls through the periwinkle-tinged circuits, some 1,300 feet of metal rails that were hung from the ceiling of the white-box Gana Art Center in Seoul, South Korea. But what really powers the experience is human interaction.

Those able to catch the exhibition last November were encouraged to pluck marbles from the tracks and reintroduce them at will, injecting a bit of randomness into the clockwork-like proceedings. And Loop had a way of influencing its audience right back. Like falling rain, the gentle trickle of marbles reaching the end of the line hushed onlookers, creating an atmosphere that was both meditative and tense. As Snarkitecture partner Alex Mustonen put it, “Architecture was pouring out of the walls in an uncontrolled way, but there was that steady drip.”

Watch a video of Loop in action below.