[(0,1),(1,2),(1,3),(2,4),(3,5),(4,6),(2,7),(0,8),(7,8),(7,9),(3,10),(6,11),(9,12),(5,13),(4,14),(9,15),(5,16),(10,17),(6,18),(8,19),(10,20)]
[(0,1),(1,2),(2,3),(3,4),(3,5),(1,5),(4,6),(5,7),(7,8),(6,9),(9,10),(6,11),(10,12),(4,13),(0,14),(9,15),(10,16),(8,17),(2,18),(7,19),(8,20)]
