Color shifting object moving east to west mid-morning.Looking NNW a single object transited east to west across approximately 60 degrees of my point of view approximately 20 degrees above the horizon. Conditions were mostly cloudy with periods of bright sunshine and blue skies, temperature around 62F.Object appeared below the cloud line, and changed color from white to reflective/metallic, to bright metallic red/orange, then back to reflective/metallic. Seemingly more square shaped and moving at a high rate of speed. Distance down range of my POV was difficult to determine as there was no point of reference. There is an Air National Guard base at PDX, the flight path of this object would have crossed out-bound traffic from the base at 45 degrees from my POV. There was no contrail or exhaust. No sound could be heard but that could have been due to distance and that I was inside the house. (Though airplanes can be heard from within the house.) I am near the out-bound flight path for the Air National Guard and in and out-bound traffic for PDX. There are also a number of smaller regional airports within a 10 mile radius. I have been observing the local skies for over 20 years. I am not a trained observer.