White sparkling lights in a triangle stationary in the sky

My two friends and I were heading north towards Olympia, Washington on I5 coming from Portland Oregon. We were past Winlock, Washington and not yet at Napavine, Washington. My friend (the driver) said to me (in the right side back seat) and his wife (who was in the passenger seat) something along the lines of hey do you also see that thing in the sky or is that just me. It was about 21:23. When I looked up there were about 6 or 7 white lights that were glittering in a triangle pattern. They were just stationary in the air above the trees forward and to the right of the car. I thought it was fireworks but they just stayed stationary glittering for about a minute while we discussed whether or not it was an airplane. I then thought I should take a picture of it and as I did the lights turned off one by one, or maybe two at a time, but not all at once and then it was gone. I got a picture with only two of the last lights on. About a minute later I took a screens! hot of where we were on the map on my phone. I have never seen anything like this before, I have no idea what it was. The driver and I are 21 and his wife is 22. He and I are college students and she just graduated.