Flares

Test Chamber 13: Place portals as shown in the image to redirect the laser. Use a time portal to move the laser into the future. Travel through the time portal (taking some damage is acceptable) to reach the future. Rearrange portals in the future to direct the laser into the target, then proceed through the exit door.

Test Chamber 14: First, travel to the present via a time portal. Summon a reflector cube and position it in the present as indicated. Use a portal to direct a laser through the first node, then use the reflector cube to guide the laser through 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 designated 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 necessary, return to the future to retrieve and re-position the future reflector cube. Finally, place the future reflector cube to direct the laser into the receiver, completing the chamber.

Test Chamber 15: Begin by passing 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. Proceed to the other side of the room and use another time portal to return to the present, now on the far side of the particle field. Place a portal on the upper wall to direct the laser to the first receiver. Return to the future and place a portal on the small wall in the laser room to aim at the receiver. Return to the present; the laser should now power 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 and retrieve the future reflector cube. Use a time portal in the laser room to bring the future reflector cube into the present. Position it to reflect the laser into the second receiver through the node. To reach the other side of the particle field, use a portal or a time portal to bypass it, ensuring you are in the present. 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.