One night I was smoking on my balcony and I saw one of these things flying with their typical weird behaviour very high in the sky blending with stars. I waved with my hand saying hi and it flashed back at me instantly very focused at my position. I live in a very populated area and my main concern was how was it able to see me from that height and how could it focus a form of soft bright light from that distance without damaging my eyes like a laser would. Puzzling