I want to make an unlevel background and then generate some test data on that using Matlab. I was not clear when I asked this question earlier. So for this simple example

for i = 1:10
for j = 1:10
f(i,j)=X.^2 + Y.^2
end
end

where X and Y have been already defined, it plots it on a flat surface. I don't want to distort the function itself, but I want the surface that it goes onto to be unlevel, changed by some degree or something. I hope that's a little clearer.