FIG. 1.

(a) Schematic picture of half-plane packing of fibers. The uniform area of fibers oriented along z direction (shown in green) is bounded by a thin transitional area (magenta) where the conductivity gradient may be important (a sketch of one possible conductivity profile is shown at the bottom of panel). (b) Schematic picture that can be used as a crude two dimensional approximation of a fold. The direction of fiber conductivity has only x and z components and all quantities are assumed to be uniform in y direction.