twoCycle      :: (Graph g) => g a b -> Node -> [Node]
twoCycle gr n = filter (elem n . suc gr) (delete n $ suc gr n)
twoCycle      :: (Graph g) => g a b -> Node -> [Node]
twoCycle gr n = filter (elem n . suc gr) (delete n $ suc gr n)
twoCycle gr n = filter (elem n . suc gr) (delete n $ suc gr n)