All these flats are yours...

Walking home yesterday I passed by a basement flat from which appeared to emanate a strangely familiar hum. I paused in front of the flat trying to place the noise before realising that it was exactly the same ominous sound emitted by the mysterious black obelisks in 2001: A Space Odyssey. The noise didn't appear to come from anywhere in particular and thought I was tempted to hang around and investigate further I was loath to hover about in front of the flat, lest I be mistaken for doer of dastardly deeds.

I returned home just now via the same route, and was surprised to discover the same baleful sound still echoing around. Again, I tried and failed to identify it's source. Given that it appears to be coming from a residential block of flats I can only speculate as to what the occupiers make of it. I'm going to keep an eye (ear) on it anyway. If it doesn't let up I may need to see what's involved in constructing a large black obelisk to set outside the place...