This is a trick that many, if not most of you, already know.
But it’s a good one and bears repeating. Quite recently I read this: “but I am still working on trying to make a box with no start and no finish and thus far have only been able to wrap my boxes on three sides”. (noted on KK’s fine project).
The process has been around for a long time, but I remember independently figuring this one out a while ago and thinking what a smile it would bring to the average guy that loves the very look of wood. So it’s “Never an old joke, just a new audience”, and here goes.
Start with a piece of wood twice your side thickness’s x the length of your long side and short side combined x the height you want. Draw a center line and mark the sides and angles as shown. Put some clear identifying marks on it too, otherwise it may be very confusing at glue up time. You might even accidentally reverse it for height, right when things are (half end grain) so quickly drying.
The technique is simple, even though what you are doing is making a box inside out.
Rip the board, dress the faces lightly and free up the lengths. Make your miters with the least amount of waste, do your other stuff (hinges, bottom, etc.) and then assemble.
Bear in mind a few things.
What you’ll end up with is a four cornered mirror match, not a waterfall (which is quite impossible), but still a very pleasing effect. The box strobes around the corners.
Flat sawn is the best top surface if you can manage it. There will be less “jump” at the corners because the edge grain will not show very much deviation through machining.
The limit to your box or frame height is the capacity of your re-saw. If it’s a band-saw cut you’ve got to be very straight. Any material machined away on those inside faces will lessen the effect.
This can easily be done with veneer as well if you have four consecutive flitches.
-- firstname.lastname@example.org : dovetail free since '53, critiques always welcome.