https://cis.temple.edu/~latecki/Courses/CIS166-05/Lectures/graph.ppt
Start at c and take a walk: {c,d}, {d,e}, {e,c} a b c d e f “Splice” the circuits in the 2 graphs: {a,b}, {b,c}, {c,f}, {f,a} “+” {c,d}, {d,e}, {e,c} “=“ {a,b}, {b,c}, {c,d}, {d,e}, {e,c}, {c,f} {f,a} 0 0 0 e 1 0 0 d 1 1 0 c 0 0 0 f 0 1 1 b 0 0 1 a e3 e2 e1 a b c d e f e1 e2 e3 e4 e5 e6 e7 0 0 1 1 0 0 0 1 0 1 1 0 1 1 0 0 0 0 0 0 1 0 ...