When I was a teenager, I was sitting on my bed which was in a bay window. The house was down the end of a lane so there were no roads facing the window. Suddenly, the whole window was lit up. The beam of light was a little shorter than the window panes. It seemed like one beam of light but then it started flickering and I realised that it was coming from something rotating clockwise. It gradually slowed down and came to a complete stop. It wasn't one beam of light but a series of rectangular lights. Then it started rotating anti-clockwise, speeding up over time until it seemed like one beam of light again and then vanished.
I don't actually know where the lights came from. I was too scared to look out the window. I suspect it was a UFO but I don't really know what it was.