I was heading south on I-5, crossing the ship canal bridge, around 9 o'clock and saw four lights in a square formation floating over lake union. They were just hovering there and didn't make a sound. At first I thought it might have been those Chinese lanterns that float up via heat from a candle but those usually flicker a little, and they weren't moving higher or in any direction, and they also were in a perfect square shape (as equidistant as I can imagine). I told my girlfriend to "look at those lights over the lake". She saw them and I asked her what she thought they were. She said she didn't know. She thought maybe some people were putting on a drone show over the lake. They were about 50 yards higher than the highway and still just hovering there, not shifting at all. I had to look forward and pay attention to the road but kept checking the rear view. My girlfriend looked at me in disbelief and then looked forward kinda zoning out. I had to look back over my shoulder since she stopped looking at them, and they were gone. I told her to look again and she agreed that they were gone. Now I know that they weren't Chinese lanterns because there is no way that all four lanterns would burn out within the same 10 seconds. I don't think they could be drones because if they went down, it is just water under the bridge unless they landed on a boat. I will never forget that night. It was like it just happened yesterday.