Obtain A Silicasistorator

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 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 direct 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 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 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. 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 field. Place a new portal on the upper wall to direct the laser to 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; an elevating platform will activate. Stand on it and place a time portal behind the node to raise the platform further, allowing you to summon a reflector cube. Place this future reflector cube on the lip above the second receiver. Travel to the future. Retrieve the future reflector cube and run into the laser room. Use a time portal in the laser room to bring the future reflector cube to the present, positioning it to reflect the laser through the node into the second receiver. To reach the other side of the particle field without going through it, use a portal or a time portal. Be in the present on the other side. 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.