Taken from Beesource: author velacreations.

As one gets older the regular Langstroth (or WARRE) upward expansion gets ever more difficult and since my honey sales have yet come close to matching hernia operations or slipped disk possibilities I tried combining the Langstroths I had using an extended bottom board.  Expansion upward has been the old go to method in Langstroth equipment but stacked and inserting heavy boxes gets old quick. A combined frame rest combines the two as you would have in a top bar hive. Best of all you have frames that are standard and not as costly. A wall can be placed between if you want, or a cut to fit strip queen excluder between the two boxes. Should the nectar flow be strong you can always put mediums on both boxes. Entrances face in two different directions and a top cover can be made from scrap political signs, Coroplast or a more insulated plywood top cover to fit both.

“I want to also add that working these hives, all of them, even the horizontal lang box described in this thread, are so much better to work than any vertical hive or a typical horizontal Lang layout. The ergonomics for the keeper are about as good as I’ve ever had.

We really need a name for the different frame orientations. This “sideways” orientation is a win/win in my book.

I’m also running screen inner covers on all of these, and that tends to keep the bees a bit calmer, too. No cracking and bumping wood pieces while I work. I can expose one frame or every frame with a flexible inner cover, so it’s easy to control the bees that way.”

Mind you, all sorts of methods can be used. An example being the divided nuc box or someone with a much more complex combination in mind.

This is quite similar to the Monk hive design.
Monk hive | Beesource Beekeeping Forums

Or this link to supering long hives as they do in Europe with fantastic plastic hive bodies.

All in all, experimentation is fun, especially when it comes to saving the beekeepers own body.