Kimmo Huosionmaa Here is one picture, where is a strange formation in the sky. I see there a square, but it could also be some kind of optical trick. I have thought that maybe this strange square is actually solar sail experiment. But there is also more explanations, and who knows about this. Maybe it is the visitor from another star, who knows, and I had the opportunity to see it from the ground. Artist's impression of solar sail (Picture II) And it can also be some optical trick. The equilateral square is very unusual form in the sky, and I must take a picture of it. The form can be caused by some kind of tests of communication systems, or it can be made on purpose, and there is one reason, what might be the reason for creating that kind of form to the sky. This could be the test of some communication lasers and for those systems must the clouds cut away from the radiation. Or this form can be caused by very large Mylar layer, what is used in the huge sails, wha...