Low rumble revealed sparkling lights, resolved into dark Triangular craft with lighting at two leading edges.As I sat in my studio, I was beginning to get ready for bed. I emptied my pockets onto my desk and thought that I should go out side before my shower. As this was the second time in a few minutes that I had thought about going outside, I stopped what I was doing, lit a smoke, and walked to the back door, opened it, and walked onto the patio. I noticed that there was a distant rumbling sound that seemed loud, loud enough that I wondered why I had not heard it inside my house. The sound was much like the sound of a jet engine, without the usual high pitched whine. Just the low frequency component of the sound like an Atlas rocket at a distance, or maybe a Harrier jet. I am a professional audio engineer, and have very good hearing. I'll also point out that I grew up in the Land Surveying business, working many years in that field before my mid 20's. Since the security lighting had activated when I went onto the patio, I reached my hand back inside the door and turned off the light to get a better look at the sky. Still hearing the rumble, I looked up to see what it could be.Above me about 60 degrees above the horizon, and due west, I saw an odd haze that would sparkle light, mostly white, with red and blue green. My first thought was that it was too low to be an airplane, and that it did not appear to be moving fast enough for flight. The sound was incorrect for it to be a helicopter. The lights seemed to twist and turn, with no discernible shape. As the sky was otherwise clear, this confused me. I noticed that there was an occasional brighter flash in red and then blue green. The object continued to morph, and as I watched, it solidified into a shape. It became an equilateral triangle with one end pointed directly south. The object seemed dangerously close to the ground and just hanging there.With my right hand outstretched to 30 inches, the object was about 9 -12 inches on each side, and about ½ to ¾ inches thick.The lights appeared along the perimeter of the two leading edges, with the brightest areas at the middle of each of those two edges. I noticed that the southern most tip of the triangle had a soft white glow, and that the remainder of the bottom was a dull dark matt finish. The light area did not appear to be illuminated, only contrasted to the rest of the surface. Much to my surprise, the bottom was not flat. There appeared to be two large rectangular areas, one on each side of the center line, and while one was along the axis of (very slow) travel, the other was at 90 degrees to it. The rectangular boxes had rounded edges. I remember thinking, that this was not a good aerodynamic shape. Another incongruity.Once the position of the object stabilized, the lighted edges were barely visible from my perspective, but the occasional brightening of the nearest mid-side light was red. I thought, maybe they were FAA lights, so I waited for the next flash. The flashing did not have consistent timing. The next time it was green, and still hazy in a digital sort of way. Checking the far side lights, I realized that they were also inconsistently colored also.. It was more like the lights were displayed as camouflage, something that would appear correct to the casual observer.Wanting to take a photo, I realized that I did not have a camera on me, and that in order to get a photo I would have to get back into the studio, grab my phone off the desk and turn it on. By this time, the object was already 45 degrees south of my position and I realized that I did not have time to get to the camera, and I decided to just continue watching. The object continued south and within a few seconds had moved to the horizon, the sparkle growing ever smaller and less distinct.I have some surveillance cameras located around my house, and I later checked to footage. I left the studio at 11:15 pm CDT to go outside, and the event lasted barely 2 minutes. I saved the recordings from the system and looked at it later, hoping that some more information could come from it. The studio camera has an audio channel, but the camera over the patio does not. I could not detect any low frequency information from the sound track, as the noise floor on such systems is rather high.