huge black morphing diamond shape no lights

I was heading from Gallatin to Portland on highway 109 when I saw a large black line appear in the sky it morphed from a horizontal line into a large diamond shape all black could see no lights only black looked to be much larger than a airplane by maybe 10 times but I could tell it was very high in the sky. The sky was clear and blue. It had folded itself open like a piece of paper looked very black and flat.. It was just stationary for about 30 second then folded back up to a black line and disappeared. I never saw it move or fly it just opened up and then closed and was not there anymore.