In the July of 2006, EA and Valve Software revealed the "final design" of the video game "Team Fortress 2". The conference and Valve screened 2 trailers showing a much more low-poly and different build of the game itself.
This includes weapons from the original Team Fortress Classic game, Near finished designs of the characters with things that weren't in the final design of the game (examples like the Spy and Heavy Weapons Guy.)
The only remaining evidences of this build are the trailers from the conference itself and images that display on the Steam games menu if you select Team Fortress 2. Many Team Fortress 2 fans have tried to recreate the lost 2006 build and the designs/models of the characters used in the early build.