/sci/ - Science & Math

A and B are correct.
The answer is A if you're watching the cube, or B if you're watching the portal. The yellow portal IS the same object as the blue portal. Moving the yellow portal relative to the cube, is exactly the same thing as moving the blue portal relative to the cube. You cannot move one half, without moving the other half. It doesn't break any law of physics or whatever, you just have to hold in your mind that there is zero distance between the in direction and out direction of each side of the hole, and there is nonzero distance between the in direction and the other in direction, same for the outs. You're not breaking anything because you're moving space which contains the cube through the portal. The sum of space is still the same. I'm fairly certain that Valve has accidentally something important.