Triangle shaped object seen west of Tacoma.I was driving north bound on a quiet road when I noticed three white lights in the sky ahead of me. I stopped the car and watched them fly northwest until they disappeared behind a forest of trees. The three lights seemed to be connected. They did not blink, flicker or change color, but remained white. There also was a flash of light coming from the left side of the object. It was white also and flashed like a strobe light at regular intervals. I could not see where the source of the flashing light. If I held up my thumb at arms length, it would not have covered the object. I have never seen anything like this before.I am a writer and amature astronomer.