Back To The Bar

Test Chamber 13: Place portals as shown in the image. Use a portal to move the laser sideways and a time portal to send it into the future. You can take some laser damage to travel into the future. Once in the future, rearrange portals so the laser hits the target. Head through the door.

Test Chamber 14: Travel to the future using a time portal. Summon a reflector cube from the switch in the center and position it in the present in the indicated area. Use a portal to bring a laser through the first node, then use the reflector cube to direct it into the next two nodes. Travel back to the future. Use portals to bring a laser into the present through the time portal, ensuring it passes through the node. Retrieve the reflector cube from the future and bring it to the present. Adjust the present reflector cube to hit all three nodes. If necessary, travel back to the future to retrieve the future reflector cube again and bring it to the present. Finally, position the future reflector cube to reflect the laser into the receiver, completing the chamber.

Test Chamber 15: Go through the particle field to the left. Place a portal where the laser hits the wall and a time portal on the opposite wall. Travel through the time portal to the future to bypass the particle field. Move to the other side of the room and use another time portal to return to the present, now on the other side of the particle field. Place a new portal on the upper wall above the laser room so the laser hits the first receiver. Travel back to the future and place a portal on the small wall in the laser room to shoot the receiver. Return to the present. The laser should be hitting the first receiver, powering an elevating platform. Stand on the platform and place a time portal behind the node to raise the platform further, allowing you to summon a reflector cube. Place this reflector cube on the lip above the second receiver. Travel to the future. Retrieve the future reflector cube and run into the laser room. Place another time portal in the laser room to bring the future reflector cube to the present. Position it to reflect the laser through the node and into the second receiver. To get past the particle field on the other side, use a portal on the other side or a time portal to go around it. You need to be in the present on the other side of the particle field. Climb the stairs and use a portal on the upper wall to hit the third receiver. Finally, move the reflector cube onto the switch to complete the chamber.