It was double chair shaped, smoothly flying, obscure, ~10 dots object.I was observing the sky (in the city), full of stars. Suddenly ~10 or more obscure dots appeared. They were flying like one object having chair shaped form. It was like parallel doubled broken stick having doubled rhomb shape ending. The strangest thing about this, it was moving quite fast, smoothly, quietly and most important - sideways (not straight). It was not changing direction or brightness. I lost it when it disappeared behind buildings.