Triangles in formation

I was sitting on my back patio which has a view northward over the Columbia River and into Franklin County, Washington and beyond. I spotted 5 objects flying in a formation in a sweeping motion in what I can best describe as a Blue Angels air show display. The objects were triangular shaped, without visible wings, nose, or tail, and reflected the sun each time they turned making them highly visible.  The weather was partial sun with clusters of low rain clouds.  The objects flew in complete unison, turning together at exactly the same time going side to side (east to west). I observed for approximately 10 seconds and asked my spouse if she could see them. She did. We watched for approximately another 10 seconds and I ran into the house to get our phones. She continued to watch for approximately 20 seconds as the objects continued to move in complete unison, turning together like a school of fish and they were much faster than an airplane covering a large dis! tance. The objects were many miles away, and moved quickly. There is an airport in the area and the objects did not behave like planes in the air. There are birds in the area and the objects did not behave like birds. When I returned with the phones approximately 20 seconds later I could not locate them on the phone screen as I attempted to record. My spouse looked down at her phone to begin recording and could not locate the objects again when she looked up. I have a flight tracker app on my phone and I checked it. The nearest plane to us at the time was above Sunnyside WA, approximately 40 miles west.