Getting home after running an errand, and just before turning into my driveway, I noted three craft at very low altitude and in a very tight pattern traveling North-Northwest over the empty block across from my house. I observe aircraft all the time day and night as a bit of a hobby, and my first reaction was, "Those craft are definitely flying lower than the 500 feet minimum." I made a full stop and jumped out of my car. The craft were traveling at about 20-25 mph. The one nearest me, less than 100 yards away, made an instantaneous stop over the apartment complex NW from my house. After about 2 seconds, it popped out of its hovering position into a new direction, perhaps 20ï¿½ï¿½ï¿½ more Easterly. I managed to see one of the other craft perform a like maneuver. It seemed that the three craft were performing a zig zagging pattern designed to incorporate stops over targets of interest. The "popping out" of the stationary position that I described above reminded me of when you try to smoothly move a handle from its position, when that handle is held in place by a spring-loaded ball which is in a pocket; what's called a "detent". Try as you might, there's always a bit of an over-acceleration of the handle as you pop the ball out of the pocket. (This information may aid our engineers in reverse-engineering their technology, I would think.) The craft were identical in size and shape. At the bottom were 4 bright, rounds areas, which initially struck me as windows during the event. Now the critical observations from an engineer's mind (mine) regarding this: The crafts stopped INSTANTANEOUSLY, not very quickly, nor really really really quickly. They stopped absolutely at an instant in time. Clearly, any living beings in those craft would have had to have enjoyed a separate gravity "bubble", so as to be fully protected from the unbelievable acceleration/deceleration the craft exhibited. The four pods on the underside of the craft had what seemed to be of a color at the moment of observation, yet within seconds after the observation, I couldn't for the life of me remember the color!! I realized a few days later that the pods had to have been the actuators of the anti-gravity drive, and that they were lighted due to ionization of the air at a certain boundary layer. The inability to discern color was due to the fact that that boundary layer is an altered state of our space/time reality. The craft made no sound whatsoever. None. The directions and speed of the craft were ABSOLUTE. I mean that the craft were traveling in absolute directions and at an absolute speed. All I can say is that if you ever witness this, you will know what I mean. I stayed outside for a good 10 minutes afterwards, just to make sure my powers of observation were not altered in some way. After hearing dogs barking in the distance, and seeing commercial aircraft flying high overhead, and seeing cars driving down the roads, I parked the car properly and went into my home. The question that kept coming into my head was, "Who ARE we?", not who were they, or anything like that, but just who the hell are WE. I had the sense that they knew that I was observing them, but that it gave them no concern whatsoever, and that I was of no interest to them. I think that they were checking up on particular individuals of interest, much like a rancher might fly his helicopter over his cattle to look for particularly marked animals.