Time Portal Device

Test Chamber 13: Place portals as shown to redirect the laser. Use a time portal to move the laser into the future, then travel through the time portal yourself. Rearrange portals in the future to direct the laser into the target and exit the chamber.

Test Chamber 14: Travel to the present via a time portal. Summon a reflector cube and position it to redirect a laser through two nodes. Travel to the future. Use portals to bring a laser into the present through the time portal, ensuring it passes through a node. Retrieve the reflector cube from the future and bring it to the present. Position the present reflector cube to hit all three nodes. Travel back to the future to retrieve the future reflector cube. Bring it to the present and position it 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. Return to the present using another time portal to be on the other side. Place a portal to direct the laser to the first receiver. Travel to the future and place a portal to shoot the laser at the receiver. Return to the present; an elevating platform will power up. 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 cube to reflect the laser to the second receiver. Travel to the future. Retrieve the future reflector cube and bring it to the present via a time portal. Position it to reflect the laser to the second receiver through the node. On the other side of the particle field (in the present), climb the stairs and use a portal to hit the third receiver. Move the reflector cube onto the switch to complete the chamber.