Example: This video shows a crystal of photorefractive BaTiO3 acting as a phase conjugate "mirror" adaptively un-distorting scattering introduced by a sheet of ground glass between it and the image source. <a href="https://www.youtube.com/watch?v=7RuHEliwJnA" rel="nofollow">https://www.youtube.com/watch?v=7RuHEliwJnA</a>