  Recursive distinctioning (RD) is a name coined by Joel Isaacson in his
original patent document describing how fundamental patterns of process arise
from the systematic application of operations of distinction and description
upon themselves. Recursive distinctioning means just what it says. A pattern of
distinctions is given in a space based on a graphical structure (such as a line
of print or a planar lattice or given graph). Each node of the graph is
occupied by a letter from some arbitrary alphabet. A specialized alphabet is
given that can indicate distinctions about neighbors of a given node. The
neighbors of a node are all nodes that are connected to the given node by edges
in the graph. The letters in the specialized alphabet (call it SA) are used to
describe the states of the letters in the given graph and at each stage in the
recursion, letters in SA are written at all nodes in the graph, describing its
previous state. The recursive structure that results from the iteration of
descriptions is called recursive distinctioning.
