graph TD
    classDef default fill:#fff,stroke:#111,stroke-width:1px;

    root(Merkle root) --> abcd(abcd)
    root --> efgh(efgh)

    abcd --> ab(ab)
    abcd --> cd(cd)

    efgh --> ef(ef)
    efgh --> gh(gh)

    ab --> a(a)
    ab --> b(b)
    cd --> c(c)
    cd --> d(d)
    ef --> e(e)
    ef --> f(f)
    gh --> g(g)
    gh --> h(h)

subgraph Leaves
  subgraph Bit 0
    a --> A
    A --> a
    b --> B
    B --> b
  end
  subgraph Bit 1
    c --> C
    C --> c
    d --> D
    D --> d
  end
  subgraph Bit 2
    e --> E
    E --> e
    f --> F
    F --> f
  end
  subgraph Bit 3
    g --> G
    G --> g
    h --> H
    H --> h
  end
end

classDef revealed fill:yellow;
class a,B,C,d,E,f,g,H revealed;