diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -0,0 +1,4 @@
+* 0.1.1.0
+  - Add `call` operation to `MonadFSM` class
+* 0.1.0.0
+  - Initial version of Motor
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 *Motor* is an experimental Haskell library for building finite-state
 machines with type-safe transitions and effects. It draws inspiration
 from the Idris
-[ST](http:/*docs.idris-lang.org*en*latest*st/state.html) library.
+[ST](http://docs.idris-lang.org/en/latest/st/state.html) library.
 
 ## Usage
 
diff --git a/motor.cabal b/motor.cabal
--- a/motor.cabal
+++ b/motor.cabal
@@ -1,5 +1,5 @@
 name:                motor
-version:             0.1.0.0
+version:             0.1.1.0
 synopsis:
   Type-safe effectful state machines in Haskell
 description:
@@ -31,7 +31,7 @@
                      , Motor.FSM.Logging
   -- other-modules:
   -- other-extensions:
-  build-depends:       base >=4.9 && <4.10
+  build-depends:       base >=4.9 && <5
                      , indexed
                      , indexed-extras
                      , CTRex
diff --git a/src/Motor/FSM.hs b/src/Motor/FSM.hs
--- a/src/Motor/FSM.hs
+++ b/src/Motor/FSM.hs
@@ -117,6 +117,7 @@
   enter (Name :: Name n) x = FSM (imodify $ \s -> lbl := x .| (s .- lbl))
     where
       lbl = Label :: Label n
+  call (FSM ma) = FSM (ilift (fst <$> runIxStateT ma empty))
 
 {- $usage
 The central finite-state machine abstraction in Motor is the 'MonadFSM' type class.
@@ -287,11 +288,26 @@
   >>>= \_ -> perish hero2
 @
 
-This is obviously quite clumsy. If anyone has ideas on how to fix or
-work around it, /please get in touch/.
-
 Had the @r@ been replaced by @Empty@ in the type signature above, it could
 have had type @NoActions m Empty ()@ instead.
+
+If the computation removes all resources that it creates, i.e. that it
+could be run as @NoActions m Empty ()@, you can use 'call' to run it
+in a row-polymorphic computation without having to list all actions:
+
+@
+doFourThings ::
+     Game m
+  => NoActions m r ()
+doFourThings = call $
+  spawn hero1
+  >>>= \_ -> spawn hero2
+  >>>= \_ -> perish hero1
+  >>>= \_ -> perish hero2
+@
+
+In a future version, 'call' might support the rows of the called
+computation being subsets of the resulting computation's rows.
 -}
 
 
diff --git a/src/Motor/FSM/Class.hs b/src/Motor/FSM/Class.hs
--- a/src/Motor/FSM/Class.hs
+++ b/src/Motor/FSM/Class.hs
@@ -33,6 +33,9 @@
   delete :: Name n -> m r (r :- n) ()
   -- | Replaces the state of an existing resource named by its 'Name'.
   enter :: Name n -> b -> m r (n ::= b :| (r :- n)) ()
+  -- | Run another 'MonadFSM' computation, with empty resource rows,
+  -- in this computation.
+  call :: m Empty Empty a -> m r r a
 
 -- | A name of a resource, represented using a 'Symbol'.
 data Name (n :: Symbol) where
diff --git a/test/Motor/FSMSpec/Game.hs b/test/Motor/FSMSpec/Game.hs
--- a/test/Motor/FSMSpec/Game.hs
+++ b/test/Motor/FSMSpec/Game.hs
@@ -10,7 +10,7 @@
 {-# LANGUAGE TypeOperators              #-}
 module Motor.FSMSpec.Game where
 
-import           Prelude                hiding (log)
+import           Prelude                hiding (log, (>>))
 
 import           Control.Monad.Indexed
 import           Control.Monad.IO.Class
@@ -87,12 +87,8 @@
 
 testTwoAddDeletes ::
      Game m
-  => Actions m '[ "hero2" !- State m Standing
-                , "hero1" !- State m Standing
-                , "hero2" !+ State m Standing
-                , "hero1" !+ State m Standing
-                ] r ()
-testTwoAddDeletes = do
+  => NoActions m r ()
+testTwoAddDeletes = call $ do
   spawn hero1
   spawn hero2
   perish hero1
@@ -101,15 +97,10 @@
     (>>) a = (>>>=) a . const
 
 testGame :: Game m => OnlyActions m '[] ()
-testGame = testTwoAdds >> testTwoDeletes
+testGame = testTwoAdds >> testTwoDeletes >> testTwoAddDeletes
   where
     (>>) a = (>>>=) a . const
 
 
-run :: Monad m => GameImpl m Empty Empty () -> m ()
-run g = runFSM (runGameImpl g)
-
 runIO :: IO ()
-runIO = do
-  run testGame
-  putStrLn "Game over."
+runIO = runFSM (runGameImpl testGame)