I was getting home on a very clear sky night. I was with a friend , we were standing at the front of my house and talking when I looked at the sky to admire the night and suddenly "an airplane-like object" caught my eye - I would say it was an airplane at the beginning because the lights were apparently like an airplane's lights (green and yellow)-I think because it was flying vertically between one star and the formation of three stars in a row. I knew something was not normal,like an airplane way of flying because of the speed and you don't see planes flying "vertically" far, far away in distance . Then the "plane" stopped in between those stars and suddenly it changed or "rotated". I actually had the impression the object rotated on its axis and show other view of it. What I saw where three lights rotating (yellow like) in a triangular shape the lights were round and they seemed to be rotating.The object remained stationary for a few seconds and then flew away like sinking in the sky at a tremendous speed until it couldnot be seen anylonger.