It can be seen as a introduction to Bayesian classification, or Matlab plotting.
function ret = drawBayesGauss2D(mu,c,prProb,ax)
% Draw Bayes classification results for 2D Gaussian distributions.
% mu: 2-by-N, mean vector for N classes.
% c: 2-by-2-by-N, cov matrices.
% prProb: 1-by-N, prior probabilities.
% ax: [xmin xmax ymin ymax], plotting ranges.
% ret: If a return value is required, it will be a 1-by-N cell array
% containing N function_handles of N posterior probabilities.
% You can use ret{i}(X,Y) to get post-prob of class i at (X,Y).