hugh triangulation of lights,nine in all,traveling with stunning cooperation and velocity,all rotating,silently and quick!

i saw a hugh triangle,50 yards by 50 by 50.each corner held three lights,white-silvery.these made the appearance of a smaller triangle three yards by three yds. by three yds.so only nine lights total.the lights three times bigger than a car headlight,and a little less bright!the lights seemed to revolve around a fixed center while each set of light rotated on its imaginary center.all rotations were counter-clockwise.swift rotations about three rotations per second.one revolution of the outer mini triangulation of lights took about one second to complete its revolving around a dark center.it was over cast.and it was flying low.about five-hundred feet up.it was deathly silent!it sailed at first sight from the north-east going to the south-west before disappearing behind a big dirt mound in the distance.i climed the hill ,headlights pointing sharply up into the night sky only two minutes earlier.this was a unique setting and one of the highest points in a large area.the hill is gone due to construction.location: int. 96 and us 131.i may haved "called attention"to the craft.it felt like it was just checking something out!perhaps the headlights of the truck beconing somewhere in the night sky.however unintentionally!
Date is approximate.  One of two reports submitted by same source for Grand Rapids, MI.  PD