Darlene Zimmerman's pattern..."Feedsack Patches". Free pattern for this keeps coming with American Patchwork magazine flyers. Also, check out Darlene's book from Public Library and use pattern for free.
Postage Stamp Quilt, 1930-1940's feedsacks, 76 x 79", 1" squares. See Oh Fransson's method of adhering squares onto a thin adhesive backing and then folding to do the quarter inch seams. Could create all of the colorful squares this way up to a white HST on the edge, and then sew to a white block of the desired size. Should make this a lot faster to assemble.