improvisation. Whilst this type of display may render visual data in a volume, it is not an addressable display and capable of only lissajous figures, such at those generated by bouncing a laser off a galvo or speaker cone. Technical challenges Known volumetric display technologies also have several drawbacks that are exhibited depending on trade-offs chosen by the system designer. It is often claimed that volumetric displays are incapable of reconstructing scenes with viewer-position-dependent effects, such as occlusion and opacity. This is a misconception; a display whose voxels have non-isotropic radiation profiles are indeed able to depict position-dependent effects. To-date, occlusion-capable volumetric displays require two conditions: (1) the imagery is rendered and projected as a series of "views," rather than "slices," and (2) the time-varying image surface is not a uniform diffuser. For example, researchers have demonstrated spinning-screen volumetric displays with reflective and/or vertically diffuse screens whose imagery exhibits occlusion and opacity. One system created HPO 3D imagery with a 360-degree field of view by oblique projection onto a vertical diffuser; another projects 24 views onto a rotating controlled-diffusion surface; and another provides 12-view images utilizing a vertically oriented louver. So far, the ability to reconstruct scenes with occlusion and other position-dependent effects have been at the expense of vertical parallax, in that the 3D scene appears distorted if viewed from locations other than those the scene was generated for. One other consideration is the very large amount of bandwidth required to feed imagery to a volumetric display. For example, a standard 24 bits per pixel, 1024×768 resolution, flat/2D display requires about 135 MB/s to be sent to the display hardware to sustain 60 frames per second, whereas a 24 bits per voxel, 1024×768×1024 (1024 "pixel layers" in the Z axis) volumetric display would need to send about three orders of magnitude more (135 GB/s) to the display hardware to sustain 60 volumes per second. As with regular 2D video, one could reduce the bandwidth needed by simply sending fewer volumes per second and letting the display hardware repeat frames in the interim, or by sending only enough data to affect those areas of the display that need to be updated, as is the case in modern lossy-compression video formats such as MPEG. Furthermore, a 3D volumetric display would require two to three orders of magnitude more CPU and/or GPU power beyond that necessary for 2D imagery of equivalent quality,