Warnings Active: Cube Dispenser, Cube Hitting Head, Jumping Into Portal, Flying Out Of Portal

Similar to Testchamber 10, make a portal on the floor of the pit and another on the extruding part of the wall above you. Repeat as before; remember to make sure that one portal (the one on the pit floor) is constant and the other (the one on the wall) is the one you move. When you reach the button, notice that you'll need a cube. The wall behind you tilts to make an angled shot; put your "wall" portal on the angled part and jump back into the "floor" portal. Don't worry about jumping all the way from that floor to the pit; only one level (from the starting point) is necessary to build the proper level of momentum to launch you. Pick up the cube and jump back down to the button, then repeat the last step to launch yourself back up to the door (no portal creation should be required, simply use the ones you made before).

Portal Walkthrough