How to construct piecewise polynomial?

I am using the following code to construct piecewise polynomial of a pascal matrix

clc
clear all
close all

% Read matrix
X=pascal(3);
disp(X);
[r c]=size(X);
i=2;
%while i==c
for j=1:c
    z=X(i,j);
    disp(z);
end
i=i+1;
%end
breaks=[0 4 10 15];
pp=mkpp(breaks,z);

Code is having error.