Inside the Boom Tube
We've been hearing about Boom Tubes since 1970 even before the first Fourth World title ever hit the stands (as you'll be reminded by the 1970 DC Comics house ad down below.) These fine Jack Kirby teleportation devices are now omnipresent in the DC Universe and that's a great thing.
But it seemed back in the day like we would only see somebody entering or exiting the Boom Tube; we never really got a view of the inside of the vessel. The recent Wonder Woman #21 changed all that and, as you can observe in the above panels from that issue, Brian Azzarello and Cliff Chiang finally gave us the vantage point we didn't realize we had been missing.
Mr. Azzarello went even a step farther and articulated a perfectly reasonable limitation to the functionality of the Boom Tube: for the passengers to be able to exit at the other end of the Tube, the entrance they had come in through has to close. Great! Why not? I like very much when a latter-day creator enriches a long-existing concept without violating the spirit of the original concept in any way.
As far as I'm concerned Brian Azzarello has earned himself the keys to New Genesis. And if the gentleman ever tires of Boom Tube travel he most certainly has my approval to ride the Dream Machine or the Glory Boat or the Mountain of Judgment. Vrooom!