    CONSTRAINED_BLOCKS
      soil1
        PARAMETER_TYPE POROSITY
        BLOCK_LINKS 1 soil2
        STRUCTURE_METRIC 2
        WEIGHING_FUNCTION 1
        WEIGHING_FUNCTION_MEAN 10.d0
        WEIGHING_FUNCTION_STD_DEVIATION 0.001d0
        ANISOTROPIC_WEIGHTS 1.d0 1.0d0 1.0d0
        RELATIVE_WEIGHT 1.0d0
        REFERENCE_PERMEABILITY 1d-12
      /
      soil2
        PARAMETER_TYPE POROSITY
        BLOCK_LINKS 0
        STRUCTURE_METRIC 2
        WEIGHING_FUNCTION 1
        WEIGHING_FUNCTION_MEAN 10.d0
        WEIGHING_FUNCTION_STD_DEVIATION 0.001d0
        ANISOTROPIC_WEIGHTS 1.d0 1.0d0 1.0d0
        RELATIVE_WEIGHT 1.0d0
        REFERENCE_PERMEABILITY 1d-12
      /
    /
