[(0,1),(0,2),(2,3),(1,3),(3,4),(1,4),(2,5),(4,5),(5,6),(6,7),(6,8),(8,9),(7,10),(9,10),(8,11),(9,11),(11,12),(12,13),(10,13),(12,14),(13,15),(14,16),(15,17),(7,17),(16,18),(15,19),(17,19),(14,20),(18,20),(18,21),(19,21),(21,22),(22,23),(20,24),(23,25),(22,26),(23,27),(16,28)]
[(0,1),(1,2),(0,2),(1,3),(2,3),(3,4),(4,5),(5,6),(6,7),(5,8),(7,8),(8,9),(6,9),(9,10),(10,11),(7,11),(4,12),(11,13),(10,13),(12,14),(13,14),(14,15),(12,15),(15,16),(16,17),(16,18),(18,19),(19,20),(17,20),(19,21),(17,21),(20,22),(22,23),(18,24),(23,25),(21,26),(23,27),(22,28)]
