Some of the cubes are filled with materials which humans created and use during their live. Most of them are not decomposable. So there might be a chance if a space ship comes back after years of light speed travel that its crew finds those plastic parts within the time capsules.
While playing with the sculpture the player sees and recognizes those materials. Within the C74 space ship landing context, we arrived on a dead planet, the players could ask themselves whether or not the shown materials are from a long gone civilization. The viewer / player could ask whether or not humanity has left these materials explicitly to send a message. So, what does the yarn mean?