Large, triangular or diamond shaped, no noise, no lights, red

I was walking the dogs late on Monday April 10th. Close to the end of our walk, as we approached a large retirement residence, I glanced up at the sky and saw a reddish coloured triangular object flying over the building. It was very dark with no lights and almost wasn’t visible. At first I thought it was a plane but it made no noise, there were no lights, and it was either much lower than any other planes have been in the area or much larger than a plane. As it flew over the retirement building (a 4 story building), the building obstructed my view of the object. I did not see it again when I finally walked past the building.