Mason's gain formula requires combining all paths and all loops judiciously. New techniques are presented in this paper to do this. All possible non-touching loop combinations can be generated systematically and represented compactly using a tree structure and/or factoring technique. Both numerator and denominator of the formula can be treated identically. The approach is simple enough to be used in teaching students Mason's gain formula as part of courses in control systems, digital signal processing, graph theory and applications, among others.
