This is the virtual tour made by James Cutler and the architectural firm Bohlin Cywinski Jackson to be approved by Bill Gates before the construction started:

Looks dated and sluggish, but you know, it IS very old by now… over 10 years if I’m not mistaken.
The idea is still pretty impressive though. Considering Bill Gates pays around a million bucks of taxes alone… ouch.

Source: Gizmodo