Australia-based inventor Mike Ando describes himself as a "professional geek." Inspired by Gehn's Holographic Imager, an object that appears in the Riven videogame…

…Ando invented what he calls the Andotrope, an omnidirectional display that presents a holograph-like image. If you and others are standing in a circle around the Andotrope, everyone sees the same video from the same perspective; in other words, if it's of a talking head, the talking head magically faces everyone at once.

Here it is in action:

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So how'd he do it?

"The main mechanism in the middle that creates the omnidirectional holographic display…consists of two specially-chosen tablets sandwiched back-to-back inside a black cylinder with viewing slits in front of the tablets, and the whole cylinder rotates at high speed (up to 1200RPM for mine, which gives an effective 40fps). Both tablets synchronise their output, effectively doubling the frame-rate by displaying two images per rotation."

"The effect is similar to a Zoetrope. Basically, I've brought a 150-year-old children's toy into the 21st century."

Ando, who goes by the handle Riumplus, explains in more detail on his Realm of Riumplus blog.