There has been a lot of discussion about the twin paradox in this forum before, but I have another angle of this problem which I have problems figuring out. What if we have these triplets, one takes off in a rocket in one direction, one takes of in another rocket in a perpendicular direction to the first one and the last one stays put at mother earth. Now the two space travelers continues their travel, near lightspeed, for one year and then turns around and returns to earth, again in one year. According to the twin paradox, the two space travelers should be younger than the one who stayed on earth, so far so good. The travelers where the ones that "worked their way around", so I have no problem accepting this. Now to the problem. What about the relation between the two space travelers? They also have been moving near lightspeed in relation to each other (not only to the one who stayed), but they have both contributed equally to this fact. No one has accelerated more than the other, so they are equal in this matter. But if traveler A looks at traveler B, he will see B moving att near lightspeed and therefore he will also see the time moving slower at B, and vice versa for B looking at A. Now, when A and B meets on earth again after their journey, how can we avoid a contradiction where it is a fact for A that B's clock has moved slower than A's and that it simultainously is a fact for B that A's clock has moved slower than B's? Of course there must be a perfectly sound explanation for this, so can somebody please give that explanation???