  function  T = Shuffle(S) 
% S is 1-by-n cell array and n is even
% T is 1-by-n cell array that is a perfect shuffle of S.

  n = length(S); m = n/2; T = cell(1,n);
  
  Top = S(1:m);
  Bot = S(m+1:n);
  for k=1:m
     T{2*k-1} = Top{k};
     T{2*k}   = Bot{k};
  end