>>716495472
Unless you happen to be doing A in a vacuum, you are also generating energy when the cube pushes are out of the way to make room for itself. If anything, A is even worse for conservation of energy since it is essentially a momentumless movement machine that lets you push things around for free. At least B's violation of conservation of energy is all contained in the portal. Even stationary portals in game will change energy if you go into a low portal and out of a higher one because of the rotation of the Earth and a different distance from the center of rotation.
