I hope no one was trying to learn from that. FD can be tough to handle for people not mathematically trained.<p>Heat equation? Why? Any second order differential equation would suffice since there is no real example with materials, temperature, properties, boundary conditions, etc. Mine as well just been reading <a href="http://en.wikipedia.org/wiki/Finite_difference_method" rel="nofollow">http://en.wikipedia.org/wiki/Finite_difference_method</a>