This pattern is called Bento Box by Tracey Brookshier.
Hope that helps.
imaquiltr

If you enlarge the picture you can see the seam lines. There are 2 squares and three rectangles in each of the four squares that make up the block. I would agree that it should be done with 2 1/2 inch strips.

webpages.charter.net/cmladronka/bminorblock.htm

i think this is what your looking for... hope it helps