function uniform(Hi, obs)
  p = ones(1, Hi) / Hi;
  for i=1:length(obs),
    p(1:(obs(i)-1)) = 0;
    for j=obs(i):Hi,
      p(j) = p(j) * 1/(j+1);
    end;
    p = p / sum(p);
  end;
  plot(1:Hi, p);
  