Pull the Sprang Cloth

Pull on the Wensleydale sprang cloth from either end and nothing much happens.

Pull out on the sides then let go and the cloth snaps back in place.

Pull kitty-corner on two points and there's this odd effect.  The cloth stretches and stays in place.  It's something like the way the wooden lattice wall of a yurt is supposed to open up.  (Not that I mess with yurts myself.)  The Z twist interlinking rows become prominent and the S twist interlinking rows recede.