subsection Compositional fields
  set Number of fields = 4
  set Names of fields = upper, lower, mantle, seed
end

subsection Initial composition model
  set Model name = function

  subsection Function
    set Variable names      = x,y
    set Function expression = if(y>=80.e3, 1, 0); \
                              if(y<80.e3 && y>=70.e3, 1, 0); \
                              if(y<70.e3 && y>-100.e3,1, 0); \
                              if(y<68.e3 && y>60.e3 && x>=198.e3 && x<=202.e3 , 1, 0);
  end
end
