withScope $ \scope1 -> do
  res1 <- acquire scope1 createR1 destroyR1
  res2 <- acquire scope1 createR2 destroyR2
  res4 <-
    withScope $ \scope2 -> do
      res3 <- acquire scope2 createR3 destroyR3
      acquire scope1 (createR4 res3) destroyR4