I don't profess to understand the software that was developed and used to "create an instrument for performance that would allow visualisation of sound in realtime", the description of a project by the creative team Quayola & Sinigagli that lets us "see sound" live. (Details about the artists' collaborative project are featured at Creative Applications Network.) I do think that, after you've watched the video below, you'll agree that what results is strange and beautiful and a wonder.
Still photos of the visualizations are available at the CAN link above.
My thanks to Visual Music for the link to CAN.