Wohmholes

In another universe, all the space-time shortcuts are audited by Wormholes Troopers. They guarantee that each galaxy in that universe has only four wormholes that lead to another galaxy (in the same universe, of course). To make travel easy, each wormhole in each galaxy has different letters: A, B C and D. If a spacecraft takes one wormhole, it will travel instantly through space-time to another p