fibbo = fix $ \fib ->
  lam $ \n ->
    newvar 0 $ \n1 ->
    newIVar $ \n2 ->
    newIVar $ \n3 ->
      update n1 n >:
      if_ (lt (deref n1) 2)
        1
        ( par (wrIVar n2 (app fib ((deref n1) - 1))) >:
          par (wrIVar n3 (app fib ((deref n1) - 2))) >:
          (rdIVar n2) + (rdIvar n3)
        )
fibbo = fix $ \fib ->
  lam $ \n ->
    newvar 0 $ \n1 ->
    newIVar $ \n2 ->
    newIVar $ \n3 ->
      update n1 n >:
      if_ (lt (deref n1) 2)
        1
        ( par (wrIVar n2 (app fib ((deref n1) - 1))) >:
          par (wrIVar n3 (app fib ((deref n1) - 2))) >:
          (rdIVar n2) + (rdIvar n3)
        )
fibbo = fix $ \fib ->
  lam $ \n ->
    newvar 0 $ \n1 ->
    newIVar $ \n2 ->
    newIVar $ \n3 ->
      update n1 n >:
      if_ (lt (deref n1) 2)
        1
        ( par (wrIVar n2 (app fib ((deref n1) - 1))) >:
          par (wrIVar n3 (app fib ((deref n1) - 2))) >:
          (rdIVar n2) + (rdIvar n3)
        )