Lights forming a triangle in the sky

I was taking out the trash, at night, as a child. I looked up through the trees and there was a point of light moving slowly at what seemed a great height.  
I watched it grow higher in the sky and noticed two other lights were traveling towards it.  I would say the lights were like they were at the points of an equilateral triangle that grew smaller as they converged.   
The lights stopped, forming a triangle in the sky about the width of six or seven full moons.  Then the lights went back the way they had come with out any noticable turning around.  There was no discernable noise.
Witness indicates that the date of the sighting event is approximate.  PD