Driving west on a suburban street in Austin, Texas at 9:25PM I observed what appeared to be a square low-flying object approaching me from the east. There were four unwavering lights, 2 red and 2 yellow. There was very little space between the lights, giving the appearance of a compact square. Strangely, it seemed that one of the sides was its leading edge, not one of the angles. I slowed down to get a better look. As the object flew over me, I watched it in the rear view mirror until it was no longer visible.
I turned right and drove about 1/4 mile south, stopping at the mailboxes on the corner to retrieve the day's mail. As I was getting out of the car, I noticed what appeared to be the same object, but now coming from the south (i.e., from behind me). It seemed to be about 300 feet in altitude and traveling about 25 mph. It made a slight humming noise. I watched as it flew above me and continued south until it again disappeared from sight, about 1/4 mile further south.
At first I thought it might be a model airplane, but the lights were too big and the hum was not characteristic of any model airplane I've ever been near. Plus, I've never known model airplanes to be flown in the evening. I discounted the possibility of small aircraft due to the non-blinking lights and lack of noise. I wondered if it was a drone, but since they are used for strictly military purposes - as far as I know - I didn't think they would have lights. Further, the square appearance and the fact that it was traveling with one of the sides forward, not one of the corner angles, seems curiously non-aerodynamic. I kept searching my mind for an explanation but, having come up with nothing, decided to file this report.