revApp#2 Nil x16 x16 revApp#2 Cons x6 x4 x2 revApp#2 x4 Cons x6 x2 dfsAcc#3 Leaf x8 x16 Cons x8 x16 dfsAcc#3 Node x6 x4 x2 dfsAcc#3 x4 dfsAcc#3 x6 x2 main x1 revApp#2 dfsAcc#3 x1 Nil Nil revApp#2 2 Nil 0 Cons 2 dfsAcc#3 2 Leaf 1 Node 2 main 1 INNERMOST hoca/dfs-flatten.trs