Triangular UFO with maroon lights over Everett Washington

I was outside with cousins when the oldest one pointed out a UFO straight up in the sky. It was a clear starry sky.  It seem really high up in the sky, if one was to hold up a quarter an arms length might have been even smaller say a nickel.  It was not round but rather an equilateral triangle.  There was a maroon light (the size of an average star) on each corner and one in between the corners (on two sides).   I feel like one side didn’t have a red light in the middle but there could have been.  The brightness of the maroon lights didn’t stand out too much from the stars probably same intensity only maroon colored. Its location was fixed in one spot (for 15 min).  The only movement it made was the rotation.  It was rotating clockwise very slowly at a constant speed, maybe one revolution per minute.  There was no sound coming from it.  We looked at it for about 10-15 minutes and then went inside to tell the adults but no one paid any attention to us.  We didn’t! go back outside.
Witness indicates that the date is approximate.  PD