Originally Posted by Motorcyclemad
I agree with BJ. That will give you a fairly common sized block to work with, and the 12" block was what you were wanting anyway.
Sorry, got sent before I finished...
The layout in the picture is a 3 x 4. If you do the math for that the finished quilt with borders would be the 46 x 64. As for the 3/8 yd pieces, they appear to be the rail fence themselves. {There appears to be a white within the small rails with two pinks, and one each with the large rails making up the 3 it is calling for. The other two pinks are in the single large rail with a white. The other large rail has the maroon, pink stripe (also for binding from what I can see) and another white.} If you are wanting a different binding you can decrease the stripe to 3/8 yd.
Green #4 and white #4 are borders.
Hope that helps.