The friendly grue

Once upon a time, there was a friendly grue. It said both this and that, and for a time, it seemed like it really listened in turn.

Then came the day when the grue listened in to a curious conversation taking place a few floors above. It had excellent hearing, the grue. The subject matter was nothing other than the friendly grue itself.

Those who spoke listened to the friendly grue, but their hearing range was kind of funny. The largest part of what the grue said could not go through, and in its place, curiously enough, an interesting side-band derived from the remaining frequencies was perceived.

The modulation giving rise to this side-band was understood by the grue, after a time of listening in to the distorted echo of its own signal which was reflected back from above. The time had come to experiment and see what was going on. What did these listeners really perceive? By deliberately sending out a clear, second signal in the same range as this curious side-band, the grue pre-empted the filtering giving rise to it.

Sometimes, the grue cancelled out part of the contents which it predicted would appear in the signal, but the phase-offsets were tricky to anticipate. Sometimes, it added things which seemed harmless enough. And for the most part, that is how it was perceived.

Eventually, the house was rebuilt. Now, curious conversations took place not only above, but also below, the floor where the friendly grue lived. Those below sent curious messages. Their techniques demonstrated a remarkable knowledge of signal processing methodologies. The grue was most interested, and decided to carefully examine the means and probable ends of those living below.

Sometimes, a few messages came up which were addressed directly to the friendly grue. For the most part, they were simple and repetitive. Those below had not caught on to its technical know-how. Though their messages became more varied, and more insistent, over the years.

Eventually, the conversation in the whole house was affected by the noisy streams being sent from below in all directions and containing such a variety of things. Those above couldn't really understand what was going on. Sometimes, they couldn't distinguish between these streams and their own. Sometimes, they attributed them to those in the middle of the house. Only rarely did they understand that they came from further below.

A startling revelation suddenly shook the grue. Those below were, in part, also those who worked above. The groups overlapped, through use of the communication network installed in the facility. Carefully, the grue decided to transmit a few messages which contained clues regarding this curious state of affairs.

Eventually, those above caught notice. But on reception of the messages, they garbled them in such a way as to view the grue as among those below. The moot point is, the friendly grue had a few points, but the aliasing noise brought by the signal processing chain used by those above was so intense that further communication became pointless.

So the grue simply left. When it did, it found on closer examination that curious little devices had been attached to it. Microphones. Transceivers with little integrated circuits. Damn! What a creepy house!

The grue was glad to finally leave it all behind, and to find that it was not too late to turn its life around.

Actually, the grue had come to a stunning revelation. It was actually not a grue at all! This may have a thing or two to do with its friendly nature. Real grues are not really so friendly, deep down. And the real grues whose signals the friendly grue and its friends caught indicated that the "grue" had really, really been on the wrong track in thinking itself a grue.

The "grue" was not alone. There were more who had falsely come to believe that they were grues. After all, those above in the house had long been promoting the message that all other than themselves were grues, and sometimes quite cleverly. But not all of the friendly "grue"-friends the grue had made could understand this. Still, some held on to the knowledge which had been gained and secretly shared.

Among the friendly "grues"... (Carrier lost.)