advent-of-code/2020/07/small_tree.hs

[
  Node {
      rootLabel = 7,
      subForest = [
        Node {
            rootLabel = 1,
            subForest = [
              Node {
                  rootLabel = 4,
                  subForest = []
                },
              Node {
                  rootLabel = 3,
                  subForest = []
                }
            ]
       },
       Node {
          rootLabel = 8,
          subForest = []
        }
      ]
    }
]