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