Black Triangle Sighting in Boulder, Colorado on 2017-11-24 21:30:00 – String of lights that moved quickly in flock of bird like formation

Taking my dog out to use the bathroom around 9:30pm mst on the se side of the house and i noticed this string of lights moving in a formation similar to a flock of birds, but it also moved like a school of fish, moving quickly through the sky, headed nw direction. i thought it was some sort of christmas lights, but the speed and movement of the object(s) pretty much shut that idea down. i couldn't keep my eyes of the object, trying to figure out what it was. the formation was mesmerizing.