Portal/Chamber 11

First Side-room
Firstly, make an accessible portal in the room you enter, and wait for the red portal gun in the middle of the next room to make a portal in the appendix room, so the blue portal looks as in the picture.

Main room 1
Now, press the button which should be situated right in front of you. Across the room a door ought to open, through which a portal can be made. Do that. Wait for a red portal to be opened where you are, and walk through it.

Second Side-room
In the room you have just entered, make a portal, where the pellets hit the wall. Wait for the pellet to go into the pellet receiver. When it has done so, make an accessible blue portal, and wait for a red portal to be created in front of the moving platform.

Main room 2
Take the moving platform to the button in the middle of the room, where you will recieve the red portal gun. Press the button, and make a blue portal in the room behind the door. Now make a red portal (Mouse 2) where you entered the room platform the last time, walk onto the moving platform, and enter the portal. From the room you enter you have direct access to the chamber lock.

"The device has been modified, so it can now manufacture two linked portals at once. As part of an optional test protocol we are proud to present an amusing fact: the device is now more valuable than the organs and combined incomes of everyone in."

- GLaDOS