Corner boxes, or something close, Bill terminology CC boxes.
A corner box always consists of a couple on the end who are original partners, each facing their original corners (who are original opposites of one another). There are four such possible boxes. They occur in pairs: whin one member of the pair exists, so does the other, e.g.; when the sides are coupled as ends. The other pair is when the heads are coupled as ends.
Note that it doesn't matter which wall is behind a designated coupled pair. If they are facing their corners, it is the same corner box. There are nominally four orientations when the sides are paired as ends, and four when the heads are paired as ends. No matter how you move them to another orientation, if you have brought their corners with them to that orientation, you can still call left allemande, promenade home.
But, ignoring orientation, and the other split box, so long as you have the same set of people in the box, you can always give a sequence of calls that doesn't chenge who is in the box, and reacy a corner box. I'm calliing all those other possibilities corner-ish, because you still have a boy, his partner, and the corners of each of them.
One of your key couples will be in the box. Half of the other key couple will be in the box. But that's also true for RR boxes. For CC, if the half is a girl, the couple must be the CCW couple (with the usual pick, couple 1), otherwise the half is a boy, and the couple must be the CW couple (with the usual pick, couple 4).