A substrate (10, 30) is joinable to at least two sheets along at least one edge of each sheet to join the sheets together along the edge to create a seam. A first substantially central longitudinal axis (16) divides the substrate into a first portion (18) between a first longitudinal edge (12) and the first longitudinal axis (16) and a second portion (20) between a second longitudinal edge (14) and a longitudinal location located along a line that is between the second longitudinal edge and up to the first longitudinal axis. The substrate includes a plurality of hooks (26) formed in the first and second portions such that substantially all of the hooks in the first portion and in the second portion face the first longitudinal axis.
