r=2;
for a=-2:0.002:1
    for b=-2:0.002:1
        x=a;y=b;
           for n=1:20
                x1=x*x-y*y+a;
                y1=2*x*y+b;
                x=x1;y=y1;
            end
            if (x*x+y*y)<r
                plot(a,b);
            end
            hold on;
    end
end