This paper model is a Turret, based on the video game Portal, the papercraft was created by Evgeniy Pelevin. Turrets serve as one of the main testing obstacles in the Portal series. Armed with almost unlimited ammunition and deadly accuracy, they will attempt to kill test subjects on sight.
Sentry Turrets are miniature tripod robots that appear in every game in the Portal series. They are seen as incapable of independent movement, but can open each side of their chassis horizontally in order to reveal two gatling guns. The central part of the chassis holds their red eye, which emits a targeting laser. Almost all of the space within the Turret is devoted to storing the ridiculously stacked ammo, explaining the nearly infinite supply of ammo when firing.
When test subjects are out of sight from the Turret's presence, they will maintain a standby state and will remain motionless with their guns retracted. Moving into their angle of sight however, will cause Turrets to deploy their guns shortly after greeting the unlucky individual before opening fire. They will continue to fire until the target is dead or moves out of sight. If the latter occurs, Turrets will briefly search for the test subject, after which they will revert to a standby state.
Turrets can be avoided, disabled or destroyed in a number of ways. The most common method is knocking them over, causing them to flail and fire wildly before deactivating. This can be done by picking them up and dropping them, or using any object to tip them over. Additionally, the Discouragement Beamss or Emancipation Grills can be used to completely destroy them.
In Portal, Turrets will shoot the glass when the player is on the other side. In Portal 2, however, Turrets will only follow the player behind glass.