Jar of Flies

I see these people coming and going, coming and going, like flies on a pile of something long dead. They pause for a second, only a fragment of a moment, before winging brightly away.
Then there are the older flies, who pause to look and grow tired and decide to rest themselves on the old dead thing for just a little while and then become part of it.
What is left? Nothing, really, just a lot of empty space, crossed by the occasional jet-black of flies alighting.