Rectangle aircraft that kept yawing left and right

As I was traveling on I five north going into downtown Portland, a reflective object in the sky caught my attention as I was driving closer towards it I noticed it was a rectangle shape object. At first I thought it was a balloon, but noticed it wasn’t getting any higher in elevation are lower and elevation. As a pilot, I am visually aware and typically know what I’m looking at in the sky. I noticed this object was lying left to right almost as if it was scanning the horizon. I would lose visual contact of it every few seconds and it almost had a camouflage/stealth appearance similar to an F1 17 aircraft. Which if you have ever looked at An F117 as it’s approaching you you would notice that they’re very hard to see from a distance unless they were at the correct angle. I have never seen something like this before in my life and thought it was kind of interesting. If I were to guess it was about the size of A pencil led if you were to extend it out in front of you