I'll go out a limb here and suggest that the pattern is printed onto the material prior to making the actual hoodie. When these sorts of designs became popular a few years back I figured that was how they were doing them - just like a lot of those designs you get at the big department stores where the design seems to carry on across but "through" the seam, it seems as if the design were screenprinted prior to actually sewing the hoodie together.
Obviously a veteran in this area can correct me if I'm wrong
I would also suggest that such a process of manufacture would call for blanks minimums in the order of 100s.