Iron Mule

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 without affecting the present. Position portals so the laser hits the target, then proceed through the door.

Test Chamber 14: Start by taking a time portal to the present. Summon a reflector cube from the center switch and position it as shown. Use a portal to bring a laser through the first node, then use it to reflect the laser into the next two nodes. Travel 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 via a time portal. Adjust the present reflector cube to hit all three nodes. If needed, return to the future to retrieve the future reflector cube again. Finally, place 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. Head 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 portal on the upper wall above the laser room to hit the first receiver. Travel 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 hit the first receiver, powering an elevating platform. Stand on the platform and shoot a time portal behind the node. This will raise the platform, allowing you to summon a reflector cube. Place this cube on the lip above the second receiver. Travel to the future. Pick up the future reflector cube and run into the laser room. Place a time portal in the laser room to bring the future reflector cube to the present. Position it to reflect the laser into the second receiver through the node. To get to the other side of the particle field without going through it, use a portal on the other side or a time portal. 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. Move the reflector cube onto the switch to complete the chamber.