Portal/Chamber 04

This chamber is another simple one to get you used to the concepts in Portal. Like the previous chamber, it has a single fixed orange end to a portal, but this time you must press a button to open the exit door.

Cube dispenser
If you look at the cube dispenser, it drops a cube into a pit. While getting into the pit is as easy as falling into it, getting back out at first seems impossible. However, if you fire the portal gun at a wall at the bottom of the pit, then walk into it, you will come back out of the orange portal. Pick up a cube and return to the main area of the chamber, then put the cube on the button and exit.

Alternately, it is sometimes possible (based on how the cube lands) to shoot a blue portal below the cube and have it fall through to the floor next to the button, without you even having to enter the pit.

"Once again, excellent work. As part of a required test protocol, we will not monitor the next test chamber. You will be entirely on your own. Good luck."

- GLaDOS

Though difficult, it is possible to get the cube through the exit doorway, thus no longer being able to exit yourself. GLaDOS will acknowledge this, and open a "complimentary escape hatch" (the exit door) for you. Similar events can occur in numerous chambers, with varying amusing lines from GLaDOS.