In Washington DC, there is a building with very interesting sound diffraction patterns and design. Sound travels in waves in straight lines until they reflect , get absorbed by, or refract off of a medium. This room was designed with bipartisanism in mind. The desks were set up so that sound would interfere with itself so that opposite members of congress could not hear what they were saying. However, the architect overlooked basic resonance, since the arches were placed just right so that members, if they were by chance friends, could hold a rather quiet but covert conversation. If only we had this capability during tests!