Portal/Chamber 07

Chamber 07 uses pellets for the second time, with the pellet receiver powering a platform to take you to the door this time.

The first portal simply needs to be placed where the pellet is making a burn mark in the wall opposite the pellet launcher; the pellet will go through the portal and come out the fixed orange end of the portal on the floor, heading into the pellet receiver. This will start the platform moving.

At first it might seem impossible to get onto the platform, but if you notice, there's a space on the ceiling above the platform at one end where a portal can be made. Fire the portal gun at the ceiling above the left side of the platform's movement range, then walk over to the fixed orange end of the portal on the floor.

Wait until the platform is directly beneath the blue end of the portal, and then fall through the orange end to land on the platform. Looking through the orange portal before falling through will help you adjust your portal placement or your fall so that you are more likely to land on the platform. Do not jump early, because the edge of the portal will limit your horizontal movement. Once safely on the platform, wait until you can jump over and proceed to the chamberlock.