High flying craft moving fast in short bursts, able to make fast corners

What I saw happened during the Leonids Perseid shower.  I wish I had written this down after the event but I am only now writing anything about 2 months later.
I wanted to go see the meteor shower and I convinced a friend to brave the IL cold of November with me and watch the sky.  I know it is best to watch the showers late night/early morning and away from city lights.  I decided to drive to Spring Lake Park outside of Macomb.  I believe what my friend and I witnessed happened around 1-2AM.
The sky was partly cloudy which mostly foiled our plans of meteor watching.  Anyway, as I was staring up I saw something move.  It was no meteor and I don’t think satellites move the way this thing was.  I told my friend I saw something strange and tried to get her to see it, which she did.  We ended up watching this thing for about 45 minutes.
But enough stage setting, this is what I saw:  It was bright and triangular shaped.  It was high up in the sky, higher than planes fly.  It moved way faster than a plane.  But the strange thing is it moved in short bursts.  When it made turns, these turns were almost immediate and in 90 degrees.  It also didn’t move across the whole sky, just in the same area of space; as if testing out its speed and maneuvers.  If you held a notecard out with your arm extended and the card facing you, the area of the card would block out the area of the sky this object moved in the entire time I watched (~45 min).  The craft would sit still for amounts of time between its bursts of high speed moving.  When it did make the sharp turns it would start out fast and then slow down just before the turn.  If I remember correctly it took a break after making turns.
Witness elects to remain totally anonymous; provides little contact information.  PD