(match (* h1 *)
  (w var)
  (match (* h2 *)
    (w node)
    (let:tree:cf
      (w leaf)
      (w{size} (let:tree:cf
        (w node)
        (let:tree:cf
          (w node)
          (w{l2xy size} (tick app))
        )
      ))
    )
  )
)