flatten (Node 3 (Leaf 5) (Leaf 7)) Infix == [5,3,7]
flatten (Node 3 (Leaf 5) (Leaf 7)) GspInfix == [7,3,5]

topspiegel (BLeaf 'a') == (BLeaf 'a')
topspiegel (BNode 5 ((BLeaf 'a') (BLeaf 'b'))) == (BNode 5 ((BLeaf 'b') (BLeaf 'a')))

spiegel (BLeaf 'a') == (BLeaf 'a')
spiegel (BNode 5 (BNode 7 (BLeaf 'a') (BLeaf 'b')) (BNode 9 (BLeaf 'c') (BLeaf 'd')))) == (BNode 5 (BNode 9 (BLeaf 'd') (BLeaf 'c')) (BNode 7 (BLeaf 'b') (BLeaf 'a'))))

wege (GNode 1 [2,3,4] Empty) 2 3 == NoWay
wege (GNode 1 [2,3,4] (GNode 2 [3] Empty)) 2 3 == OneWay