Different shapes can be generated by sticking square tiles edge to edge. The figures below show examples of FOUR unique shapes generated by sticking FIVE square tiles in the given manner. Please note that shapes a, b, c and d of example 4 are NOT DIFFERENT from each other as any of them can be generated by simple operation(s) of rotation or flipping the others. What is the total number of unique shapes (including the four shown) that can be generated by sticking FIVE square tiles along their edges? [Figure: see page 4 of source PDF]