Extention of markov chain from first order to second order?

Question

Below is my matlab code snippet for generating first order markov chain. I am having trouble with extending to 2nd order markov chain. Can some one help me in doing so? Any suggestions, hints, links, pseudo-code, algorithm, python or matlab snippets would be helpful.

cdist is the cumulative distribution vector (size-28*1) my 27 symbols. I am writing the output to file called chain.p and q are uniform random numbers. CTRANS is the cumulative matrix corresponding to my first order transition matrix TRANS (which is not shown here, its size is 729*27). CTRANS besides being the cumulative version also has a row vector of zeros appended on top for programming ease. cols is the column size of CTRANS.

%generate sequence according to distribution and transition matrix
fileID = fopen('chain','w');
for k=1:10000
    p=rand;
    for l=2:numel(cdist)%2 to 28
        if ((p >= cdist(l-1)) && (p <= cdist(l)))
            fprintf(fileID,'%s\n',num2str(l-1));
            q=rand;
            for m=2:cols%2 to 28
                if ((q >= CTRANS(l,m-1)) && (q <= CTRANS(l,m)))
                    fprintf(fileID,'%s\n',num2str(m-1));
                end
            end
        end
    end
end
fclose(fileID);

I am struggling with the second order case. I can provide more details if required. My input data from where I extract the statistics is english text of length around 4000 characters. I have removed the punctuations etc and converted capital letters to small letters, so now there are 27 symbols where number 1 represents 'a' till 26 represents 'z' and 27 for space. Also I have created the bi-gram distribution vector for the second order case.