Seems the Americans don't use the word 'box' any more.
Sir, that is only in the USAF. Normal Americans don't play that game. (We play others, of course)
Apparently it has been officially replaced by container. So when you go flying on ops, you actually go into the container. And innovative thinking is now thinking outside the container.
When a nautical person needs to use the head, he need not use a containter more complex than a porcelain bowl ... this cause some wry amusement in my tour with the USAF. (I were USN at the time)
Head is another word that has been replaced too - cranium. Missiles no longer have warheads, but warcraniums.
More USAF silliness.
I didn't know whether to laugh or cry when I heard that at a meeting during the week. But it seems the otherwise seemingly normal and vaguely sane USAF Colonel was deadly serious.
As noted above, it was due to the overuse of head and box in double entendres and wimmin in the cockpit.
So to speak ...
By the time I was done with my USAF assignment, I was ready to hit the overhead whenever I heard cranium or container in its silly context, so to speak, not to mention going downtown. I was tempted to grab a few of them by their stacking swivels and slam them against the bulkheads until they saw sense.