Chamber 11

Place the first portal on the chequered panel in the middle of the floor and the second portal underneath the transportation beam in the far left corner.

Step into the transportation beam until you reach the ceiling.

Fire a portal onto the slanted wall opposite you.

Pick up the Experimental Cube from the platform you land on.

Carry the Experimental Cube to the left-hand corner where the laser beam is powering up the transportation beam.

Set the Experimental Cube down so it obstructs the laser beam.

Place a portal nearby and walk through it to return to the top of the room.

Stand over the edge near the drop (leading to the laser beam) and set a portal on the slanted wall to your left, ensuring another portal remains on the slanted wall on the top half of the chamber.

Walk over the jump plate to be carried through the portals to the Displacement Cube.

Pick up the Displacement Cube and set it down beside the Experimental Cube.

Set the Displacement Cube down in front of the laser beam.

Fire a portal into the wall where the laser beam is now hitting.

Grab the Experimental Cube and jump through the portal with it.

Set the Experimental Cube down on the chequered floor panel on the upper floor.

Locate the beam receptor near the lifts on your left.

Use your portals to direct the laser beam from the Displacement Cube at this receptor. Use the small vertical corner to guide the beam properly.

The first lift will lower; stand on it and face the Displacement Cube ahead.

Note the color of the portal you used near the Displacement Cube and fire this portal anywhere else to break the laser beam. This will raise the platform you are on.

Move the Displacement Cube from the laser beam's line of fire.

Use the transportation beam to carry the Experimental Cube up to the switch on the ceiling.

Once the Experimental Cube is pressing the switch, step onto the second platform.

Use a portal to break the transportation beam completely.

The platform will raise upwards, allowing you to escape via the exit.