Karl holds something up. "Originally there was a cover. This is only for storing."

You are not sure that you understand exactly what he's getting at, but you assume that he is speaking about some kind of reorganization of the archived materials.The species are lined up alphabetically, in English, Latin and German. S means that they are mammals. V stands for Vogel, birds.

“Sometimes the recordings are difficult to categorize”, he admits.

You raise your eyebrows, and Karl makes an attempt to clarify:

“Typically there are lots of animals in the same place. I didn’t know what animal called, and there was no chance to change the magnetic tape in between”

In between what? You are tired, so you just nod. Karl continues, making small, jittery movements with his fingers.

“Of course, you could change, but you didn’t know what will be next!"

You reply with a short silence.

Karl ignores your silence, and continues ranting, as if speaking to himself. “These small inconsistencies in categorization might seem insignificant, but they sometimes cause small earthquakes inside the walls of the archive” You keep nodding sympathetically. “Wait, what?” He assures you that it's nothing serious, just a slight rumble, a low-frequency hum, not enough to cause a total collapse of the building, but still... there might be leakage.