Onboard Computer

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. Enter the time portal yourself (taking some damage is okay) to reach the future. Rearrange portals in the future to direct the laser into the target, then exit through the door.

Test Chamber 14: First, travel to the present using a time portal. Summon a reflector cube and position it in the present as shown. Use a portal to guide a laser through the first node and then reflect it into the next two nodes. Travel to the future. Use portals to bring a laser into the present through the time portal, ensuring it hits the designated node. Retrieve the reflector cube from the future and bring it to the present via a time portal. Position the present reflector cube to hit all three nodes. If adjustments are needed, travel back 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: 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 reach the future, bypassing the particle field. Proceed 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 to direct the laser to the first receiver. Travel back to the future and place a portal on a small wall in the laser room to aim at the receiver. Return to the present; the laser should still 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 bring it back to the present using a time portal within the laser room, positioning it to reflect the laser into the second receiver through the node. To reach the other side of the particle field without traversing it, use an existing portal or a time portal. Ensure you are in the present on the other side. Climb the stairs and place a portal on the upper wall to hit the third receiver. Move the reflector cube onto the switch to complete the chamber.