[(0,1),(0,2),(1,2),(1,3),(3,4),(2,4),(4,5),(3,6),(5,7),(6,7),(5,8),(6,9),(7,10),(8,11),(9,12),(10,12),(9,13),(8,13),(11,14),(12,15),(13,16),(10,17),(11,18)]
[(0,1),(1,2),(2,3),(3,4),(2,4),(0,5),(5,6),(1,6),(4,7),(6,8),(3,9),(8,9),(7,10),(9,10),(8,11),(7,11),(11,12),(12,13),(12,14),(5,15),(13,16),(13,17),(10,18)]
