Bright light that zig-zagged in the sky. Speed of pattern and size is impossible with human-made aircraft.

I was about twelve or so when this happened.  My friend and I wanted to sleep on the back porch.  We were laying there and I was a light which was brighter than the stars around it.  I couldn't tell what shape it was because it was very high in the atmosphere.  This light was moving from northeast to southwest.  It moved along for awhile and I thought it was just a satellite or something.  Then it did a very sharp u-turn and when it was returning the way it came from it did a zig-zag type pattern on it's way.  This pattern I know is not possible with any type of jet or anything we have.  The size of the zig-zag pattern was a decent size in the sky and as fast as this thing was making it the pattern had to be miles long from zig-zag tip to zig-zag tip.  This frightened me so bad I have been freaked out 'til this day because I know there is something very strange out there.
Date is approximate.  PD