<image> The embroidery of a certain ethnic group has a long history. Figures (1), (2), (3), and (4) show their simplest embroidery patterns. These patterns are all composed of small squares. The more small squares there are, the more beautiful the embroidery is. Following the same pattern (the same arrangement of small squares), let the nth figure contain \( f(n) \) small squares. 
(1) Find the value of \( f(6) \);
(2) Using intuitive reasoning and the "inductive reasoning method," deduce the relationship between \( f(n+1) \) and \( f(n) \), and based on the relationship you obtain, derive the expression for \( f(n) \).