

Look overhead for a small gap through which you can spot a lightly-colored ceiling surface. There are more pistons in the next room, though they're not as tall. Next, drop back down to the ground level and create a nearby orange portal to warp into the hall high above.

Fire a blue portal into the passage, hitting one of the walls inside. There's a small passage near the ceiling that leads out of this large room. Hop onto the center piston when it's in the down position and ride it up. Continue through the hall to a room with a number of very tall pistons. You should be able to pass through the nearby blue portal and jump diagonally to reach the ledge and continue. Face the ledge you're trying to reach, then fire an orange portal onto the wall just right of the ledge. Once you've wormed your way into the next small area, look for a ledge overhead. You can fire a blue portal through the mesh barrier, then backtrack to the previous room to drop back through the nearby orange portal and warp into the new area that was blocked by the mesh. Follow the sign's directly, going left to a dead-end. From the top of the slab you can jump onto the horizontally-aligned piston in the corner of the room that'll push out, letting you jump onto a ledge with a hand-scribbled sign in red.
