ro = 0.7


kRep = 30;
nsamples = 1000;
dra = [];
for i=1:nsamples
    t21 = rand()*6 - 3;
    for k=1:kRep    
        t12 = mvnrnd(ro*t21,(1-ro*ro));
        t21 = mvnrnd(ro*t12,(1-ro*ro));
    end
    dra = [dra;[t12 t21]];
end
scatter(dra(:,1),dra(:,2))