Threshold

What's the thing with flies? Going into a house with ease but not able to get out, Jets around my living room with no purpose till it dies, On my windowsill it lays until I sweep it in the bin, A life wasted, trapped, defeated all because it went inside, Some die of suffocation, or fall victim to a spiders web, Some are slower and get caught by my lurchers eagle eyes, Some escape when I open a window and guide it through, They're the lucky few, lucky to be alive, But most die, in the house, they where so determined to fly.