diff --git a/moffy-samples-events.cabal b/moffy-samples-events.cabal
--- a/moffy-samples-events.cabal
+++ b/moffy-samples-events.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           moffy-samples-events
-version:        0.1.0.0
+version:        0.1.1.0
 synopsis:       Events for sample codes of moffy
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/moffy-samples-events#readme>
 category:       Control
@@ -28,6 +28,7 @@
 library
   exposed-modules:
       Control.Moffy.Samples.Boxes.Viewable
+      Control.Moffy.Samples.Event.Area
       Control.Moffy.Samples.Event.CalcTextExtents
       Control.Moffy.Samples.Event.Delete
       Control.Moffy.Samples.Event.Mouse
@@ -38,6 +39,7 @@
       Control.Moffy.Samples.Followbox.Handle
       Control.Moffy.Samples.Followbox.TypeSynonym
       Control.Moffy.Samples.Followbox.ViewType
+      Control.Moffy.Samples.Handle.Area
       Control.Moffy.Samples.Handle.Random
       Control.Moffy.Samples.Handle.TChan
       Control.Moffy.Samples.Run.TChan
@@ -58,6 +60,7 @@
     , aeson
     , base >=4.7 && <5
     , bytestring
+    , containers
     , http-conduit
     , moffy
     , monads-tf
@@ -86,6 +89,7 @@
     , aeson
     , base >=4.7 && <5
     , bytestring
+    , containers
     , http-conduit
     , moffy
     , moffy-samples-events
diff --git a/src/Control/Moffy/Samples/Event/Area.hs b/src/Control/Moffy/Samples/Event/Area.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Moffy/Samples/Event/Area.hs
@@ -0,0 +1,31 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE DataKinds #-}
+{-# OPTIONS_GHC -Wall -fno-warn-tabs #-}
+
+module Control.Moffy.Samples.Event.Area where
+
+import Control.Moffy
+import Data.Type.Set
+import Data.Bool
+
+type Point = (Double, Double)
+
+data SetArea = SetAreaReq Int Point Point deriving (Show, Eq, Ord)
+numbered [t| SetArea |]
+instance Request SetArea where data Occurred SetArea = OccSetArea deriving Show
+
+setArea :: Int -> (Point, Point) -> React s (Singleton SetArea) ()
+setArea i (lu, rd) = await (SetAreaReq i lu rd) $ const ()
+
+data GetArea = GetAreaReq Int deriving (Show, Eq, Ord)
+numbered [t| GetArea |]
+
+instance Request GetArea where
+	data Occurred GetArea = OccGetArea Int Point Point deriving Show
+
+getArea :: Int -> React s (Singleton GetArea) (Point, Point)
+getArea i0 = go >>= \(i, a) -> bool (getArea i0) (pure a) (i == i0)
+	where
+	go = await (GetAreaReq i0) \(OccGetArea i lu rd) -> (i, (lu, rd))
diff --git a/src/Control/Moffy/Samples/Handle/Area.hs b/src/Control/Moffy/Samples/Handle/Area.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Moffy/Samples/Handle/Area.hs
@@ -0,0 +1,25 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE TypeOperators #-}
+{-# OPTIONS_GHC -Wall -fno-warn-tabs #-}
+
+module Control.Moffy.Samples.Handle.Area where
+
+import Control.Concurrent.STM
+import Control.Moffy.Handle
+import Control.Moffy.Samples.Event.Area
+import Data.Type.Set
+import Data.OneOrMore qualified as Oom
+import Data.OneOrMoreApp qualified as App
+import Data.Map qualified as M
+
+handle :: TVar (M.Map Int (Point, Point)) -> Handle' IO (SetArea :- Singleton GetArea)
+handle vm = handleSetArea vm `merge` handleGetArea vm
+
+handleSetArea :: TVar (M.Map Int (Point, Point)) -> Handle' IO (Singleton SetArea)
+handleSetArea vm (Oom.Singleton (SetAreaReq i ul dr)) = do
+	atomically . modifyTVar vm $ M.insert i (ul, dr)
+	pure . Just $ App.Singleton OccSetArea
+
+handleGetArea :: TVar (M.Map Int (Point, Point)) -> Handle' IO (Singleton GetArea)
+handleGetArea vm (Oom.Singleton (GetAreaReq i)) = do
+	Just . App.Singleton . uncurry (OccGetArea i) <$> atomically ((M.! i) <$> readTVar vm)