Creating a four-corner grain match

I've seen mitered boxes where the grain figure wraps around all four corners of the box, but I've never understood how this is done. Can you tell me the secret?
—Robert Cook, Thetford, N.H.

Four-corner grain matching (sometimes called continuous grain matching) is one of those techniques that can make you scratch your head, Robert—until that aha! moment when you discover how it's done. The trick is to resaw a thick blank into two identical, thinner boards. The resawn faces become the outside faces of your box. By removing a minimum of material when miter-cutting the blanks, you preserve the grain wrap around each corner.

When planing, remove the bulk of the material from the outside faces of the blank. This preserves the grain match of the bookmatched halves.
Start with a blank at least ¹⁄₈ " thicker than twice the thickness of the finished walls of your box. Joint and rip the blank to the finished width of the box walls. Trim the blank to about ¹⁄₄ " longer than the combined length of one side and one end of the box [Drawing 1]. Resaw the blank into two halves and mark them to maintain the original orientation. Then plane them both to final thickness. These pieces will exhibit mirror-image grain patterns on the resawn faces.

Lay out and label the parts of your box on the blanks, numbering the mating corners [Drawing 1]. Miter-cut the parts to length, trimming the same amount from the ends of both blanks to maintain the grain match [Drawing 2]. Dry-assemble the box, orienting the parts so the numbered ends mate up correctly [Photo], then glue them up for a box with a near-perfect grain match on all four corners.