Here is a cut-away view of a typical Iraqi cinder block construction building which lines main supply routes through the city of Mosul. Inside a sniper has created a fireing position from the 3rd story, looking down through a curtain and out a 2nd story window. This position allows him to place fire at traffic moving up the route outside, without giving away his position as his muzzle flash would not be visible to counter snipers who might be in other buildings in the area.
A SEAL team that was working in our Area of Operations found this sniper in short time. they located him using the sound of his shots and eventually circled around behind him and neutralized him in his sniper hide.