At least two companies, IO2 Technology of Hermosa Beach, California, and FogScreen in Seinäjoki Technology Center, Finland, have working prototypes for systems that broadcast two-dimensional images into thin air.

IO2 Technology’s Heliodisplay, the size of a breadbox, projects images onto a cloud of water vapor diffused into the air rather than on a screen. Observers can control the virtual characters as they would on a computer screen, but instead of using a mouse, they use their hands.