npart=6000;
ns=600;
nslice=floor(npart/ns);
nturn=2000;
stddata=zeros(nturn,1);
xpart=(2*rand(npart,1)-1);
data=zeros(npart,1);
for i=1:npart
    data(i,1)=xpart(i);
end;
data0=data;
 for j=1:nturn
 dataslice=reshape(data(:,1),[ns,nslice]);   
 for islice=1:nslice
     avgslice=mean(dataslice(:,islice));
     for i=1:ns
         data((islice-1)*ns+i,1)=data((islice-1)*ns+i,1)-avgslice;
     end;
     end;
stddata(j,1)=std(data(:,1));
data2=data;
data=data(randperm(npart),:);
 end;
 indxdata=1:npart;
 plot(indxdata,data0(:,1),indxdata,data2(:,1));