Critical Coulomb Compressional Wedge. Particles within the deforming mass have a coefficient of interparticle friction of 0.30; the friction coefficient between internal particles and the rigid row of balls at the base is 0.15, defining a weak horizontal decollement. As the left boundary moves inward, the mass is compressed, dominantly causing folding and distributed flow of the mass; the colored layers are observed to thicken. The wedge forms a "critical taper" which is apparently maintained as deformation proceeds.
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