  The Schelling model is a simple agent based model that demonstrates how
individuals' relocation decisions generate residential segregation in cities.
Agents belong to one of two groups and occupy cells of rectangular space.
Agents react to the fraction of agents of their own group within the
neighborhood around their cell. Agents stay put when this fraction is above a
given tolerance threshold but seek a new location if the fraction is below the
threshold. The model is well known for its tipping point behavior: an initial
random (integrated) pattern remains integrated when the tolerance threshold is
below 1/3 but becomes segregated when the tolerance threshold is above 1/3.
  In this paper, we demonstrate that the variety of the Schelling model steady
patterns is richer than the segregation-integration dichotomy and contains
patterns that consist of segregated patches for each of the two groups
alongside patches where both groups are spatially integrated. We obtain such
patterns by considering a general version of the model in which the mechanisms
of agents' interactions remain the same but the tolerance threshold varies
between agents of both groups.
  We show that the model produces patterns of mixed integration and segregation
when the tolerance threshold of most agents is either below the tipping point
or above 2/3. In these cases, the mixed patterns are relatively insensitive to
the model's parameters.
