Just thinking out loud here. What if you started with two center squares, wrong sides together, one Thanksgiving colors, the other Christmas colors. Take the next size log, again two of them, place one right side together on top of the center square, the other right side together on bottom of the center square, matching Thanksgiving color with Christmas color. Repeat for all the logs around the log cabin block. You would wind up with a log cabin block that was all Christmas on one side, Thanksgiving on the other. If you make a bunch of them you could theoretically join them in a quilt-as-you-go manner, with sashing strips. Was that how it was done?