I have been asked how many angels can fit on top of a Christmas tree… in truth, it depends very much on the angel. This one is a class V4, which have a particularly high density and largish size; a class B2, on the other hand, could hang out with about seven million of its friends and they would not even be visible to the naked eye. This V4 has dislodged a few hundred thousand B2s, who are all chittering in angry chorus; I believe it sounds like the tinkle of tiny bells…