[(0,1),(1,2),(0,2),(2,3),(1,3),(3,4),(4,5),(5,6),(6,7),(7,8),(4,8),(5,9),(6,10),(7,11),(8,12)]
[(0,1),(1,2),(0,2),(2,3),(1,3),(3,4),(4,5),(5,6),(6,7),(7,8),(4,8),(5,9),(6,10),(7,11),(8,12)]
