A formation of bouncing lights was flying over the IJsselmeer.We all live in anna poulowna, iots a small duth town near den helder. We had a meeting to go out and do our paperround. As we usually do,we drove on our bikes towards the distribution office, as one of us yelled, kijk naar het water, we did that and we saw a Formation of strange bouncing lights above the IJsselmeer. They moved around in a bouncing pattern, not emmitting any sounds. We stopped and we looked upon them with incredible awe. Then they broke their pattern and made around circle with the opening towards us. Maybe they seen us or something. Than they made an awfull sound. Like a piece of chalk over the schoolbord, and they shot up into the air and they dissapeard. We stood by the water, the surface, normally very calm in no-wind conditions, was very wild and wavy. We quikly drove towards the office.