Beat Saber is like Star Wars meets Dance Dance Revolution, and involves slicing blocks with light sabers to the beat of popular tracks. It's played with a Vive VR headset on Steam VR (or on PlayStation VR and Oculus VR) and players use Lighthouse and other controllers to move the sabers.

To eliminate tracking errors, Valve had calculated what it thought were the maximum human speeds, but it turned out they were wrong. "For example, if our math says you are *behind* your only basestation, clearly we made a mistake, because we wouldn't be getting any signal from behind the basestation," the company said. "One of these checks relates to how fast we thought it was physically possible for someone to turn their wrist. It turns out that a properly motivated human using a light enough controller could go faster (3600 degrees/sec!) than we thought."

That means players can flick their wrists 90 degrees in about 1/40th of a second, about half fast as the refresh rate on a Vive headset. To see what that looks like in real life, check the video posted by Felps Live (above), where he displays incredible speed and coordination in slicing up boxes. Suffice to say, this is the kind of fun publicity VR gaming needs to become more mainstream.