When a person gets tired, he subconsciously approaches the windows and looks at the sky. Unlike the earth, which is hidden in reinforced concrete, the sky is still free. In the near future, people can deprive and the opportunity to enjoy the blue sky and clouds, closing it with protective screens, but so far this is not, it is worth rejoice and enjoy the blue, rays of the sun, enjoy the rain and rejoice at pure snow. This beauty is opened to us windows, just approach them and look at the sky. It, even being gloomy and cloudy, still gives calm, stability of hope and confidence.