I say a rectangular shape in the sky.

3/20/2007 Hello, What I saw was not an actual spacecraft.  It was, and looked liked like, a window or rectangle floating above the north end of Seattle, WA.  I was on the east side of Lake Washington driving west across an over ramp from I-405.  It seemed visible enough that this would have been reported on the news.  I heard nothing about it.  Therefore, I chalked it up as something unusual but since no one else saw it, it would be like talking to a brick wall if I tried to explain to anyone what I saw.
However, later I talked to someone that saw the same thing quite a few years prior.  It isn’t really anything fantastic enough to report so we both just left it alone.
I lost sight of the one I was looking at because of traffic behind me and no place to pull over for a longer look.  But it was there, just sitting in the sky and not moving. It had definite rectangular shaped perimeter to it and from I saw there was clear sky looking through the inside of the rectangle.
Has this type of event ever been reported before?  After reading a sighting by Col. Phillip Corso he mentioned he saw a UFO fly straight up from the ground and through a rectangular opening in the sky and it was gone.  He reported this while on active duty in the army.
((name deleted))