Scientists have created something that does not block light or air, but blocks sound. They realized that a donut shaped object would be able to block the most of the sound waves. It was a 3d printed ring what they put on the end of a PVC pipe and a loudspeaker on the other side ,what did they hear, nothing. The reasoning behind this is that the sound waves bounce off the ring and what you hear is inaudible to humans. This can help society in the future with noise.