After jumping over the hidden turrets beam, position your first portal on the wall directly facing the three turrets on the right-hand side. Now stand on the red button and set the second portal directly under the laser beam.
This’ll cause the beam to travel directly into the path of the three turrets directly ahead (causing them to explode in a fiery ball of mechanical death). Once they’re all gone, run over to the Companion Cube and let go of it on the red button. Now run back to the Displacement Cube (by jumping over the laser beam).
Welcome back to Aperture Science, a world where your Companion Cube isn't you're only company. Take control of Chell once again in Valve's sequel which takes you on an humorous and puzzling adventure and in our detail-packed guide we'll show you:
How to solve every test chamber first time.
Conquer every co-op chamber with a friend.
Loads of High Definition screenshots and videos showing you the solutions to every single chamber.
High Definition strategy videos for every achievement in the game.
Uncover all of the hidden secrets and Easter eggs.