diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,12 @@
 # Revision history for wild-bind-task-x11
 
+## 0.2.0.0  -- 2018-01-01
+
+* Modify constraints of `wildNumPad` and `wildNumPad'` functions
+  because of the change in wild-bind-x11-0.2.0.0 package.
+* Add `WildBind.Task.X11.Seq.Example` module.
+
+
 ## 0.1.0.1  -- 2016-09-22
 
 * First version. Released on an unsuspecting world.
diff --git a/src/WildBind/Task/X11.hs b/src/WildBind/Task/X11.hs
--- a/src/WildBind/Task/X11.hs
+++ b/src/WildBind/Task/X11.hs
@@ -39,9 +39,9 @@
 import WildBind.Indicator
   ( Indicator, NumPadPosition(..),
     updateDescription, getPresence, setPresence, togglePresence, quit,
-    withNumPadIndicator, wildBindWithIndicator
+    withNumPadIndicator, wildBindWithIndicator, toggleBinding
   )
-import WildBind.X11.Internal.Key (KeySymLike, ModifierLike)
+import WildBind.X11.Internal.Key (XKeyInput)
 
 -- | A convenient function to create an executable action with X11
 -- 'FrontEnd' and 'Indicator' for a number pad.
@@ -58,14 +58,12 @@
 --
 -- For the input type @i@, you can use 'NumPadUnlocked' or
 -- 'NumPadLocked'.
-wildNumPad :: (NumPadPosition i, KeySymLike i, ModifierLike i, Describable i, Ord i, Enum i, Bounded i)
+wildNumPad :: (NumPadPosition i, XKeyInput i, Describable i, Ord i, Enum i, Bounded i)
               => Binding ActiveWindow i -> IO ()
-wildNumPad orig_binding = wildNumPad' $ \ind -> orig_binding <> help_binds ind where
-  help_binds ind = binding $ map (\input -> (input, Action "Toggle description" $ togglePresence ind)) help_likes
-  help_likes = filter ((== NumLDivide) . toNumPad) $ enumFromTo minBound maxBound
+wildNumPad orig_binding = wildNumPad' $ \ind -> orig_binding <> toggleBinding ind NumLDivide
 
 -- | A more flexible version of 'wildNumPad'. It passes you an
 -- 'Indicator', and uses the 'Binding' you return as-is.
-wildNumPad' :: (NumPadPosition i, KeySymLike i, ModifierLike i, Describable i, Ord i, Enum i, Bounded i)
+wildNumPad' :: (NumPadPosition i, XKeyInput i, Describable i, Ord i, Enum i, Bounded i)
                => (Indicator ActiveWindow i -> Binding ActiveWindow i) -> IO ()
 wildNumPad' create_binding = withNumPadIndicator $ \ind -> withFrontEnd $ wildBindWithIndicator ind (create_binding ind)
diff --git a/src/WildBind/Task/X11/Seq/Example.hs b/src/WildBind/Task/X11/Seq/Example.hs
new file mode 100644
--- /dev/null
+++ b/src/WildBind/Task/X11/Seq/Example.hs
@@ -0,0 +1,60 @@
+-- |
+-- Module: WildBind.Task.X11.Seq.Example
+-- Description: An example of WildBind.Seq
+-- Maintainer: Toshio Ito <debug.ito@gmail.com>
+--
+-- This is an example of using "WildBind.Seq" module to build bindings
+-- for key sequences. See the source.
+--
+-- @since 0.2.0.0
+module WildBind.Task.X11.Seq.Example
+       where
+
+import Data.Monoid ((<>))
+
+-- Following is from wild-bind package
+import WildBind (Binding, wildBind, binds, on, run)
+import WildBind.Seq
+  ( SeqBinding,
+    prefix, fromSeq, toSeq, withCancel, withPrefix
+  )
+
+-- Following is from wild-bind-x11 package
+import WildBind.X11
+  ( XKeyEvent, ActiveWindow,
+    withFrontEnd, ctrl, press
+  )
+import qualified WildBind.X11.KeySym as Sym
+
+main :: IO ()
+main = withFrontEnd $ wildBind myBinding_simple
+
+-- | 'prefix' is a simple API to build a binding for key sequence.
+myBinding_simple :: Binding ActiveWindow XKeyEvent
+myBinding_simple = prefix [ctrl Sym.xK_g] [ctrl Sym.xK_x] $ binds $ do
+  on (ctrl Sym.xK_f) `run` putStrLn "C-x C-f"
+  on (ctrl Sym.xK_o) `run` putStrLn "C-x C-o"
+  on (ctrl Sym.xK_c) `run` putStrLn "C-x C-c"
+
+-- | You can combine 'SeqBinding' objects together to build a complex
+-- binding for key sequence.
+myBinding_complex :: Binding ActiveWindow XKeyEvent
+myBinding_complex = fromSeq $ withCancel [ctrl Sym.xK_g] seq_binding
+  where
+    seq_binding :: SeqBinding ActiveWindow XKeyEvent
+    seq_binding = (withPrefix [ctrl Sym.xK_c] c_binding)
+                  <> (withPrefix [ctrl Sym.xK_x] x_binding)
+    c_binding :: SeqBinding ActiveWindow XKeyEvent
+    c_binding = toSeq $ binds $ do
+      on (ctrl Sym.xK_n) `run` putStrLn "C-c C-n"
+      on (ctrl Sym.xK_p) `run` putStrLn "C-c C-p"
+    x_binding :: SeqBinding ActiveWindow XKeyEvent
+    x_binding = (withPrefix [ctrl Sym.xK_Return] xret_binding)
+                <> plain_x_binding
+    plain_x_binding :: SeqBinding ActiveWindow XKeyEvent
+    plain_x_binding = toSeq $ binds $ do
+      on (ctrl Sym.xK_f) `run` putStrLn "C-x C-f"
+    xret_binding :: SeqBinding ActiveWindow XKeyEvent
+    xret_binding = toSeq $ binds $ do
+      on (press Sym.xK_f) `run` putStrLn "C-x RET f"
+      on (press Sym.xK_c) `run` putStrLn "C-x RET c"
diff --git a/wild-bind-task-x11.cabal b/wild-bind-task-x11.cabal
--- a/wild-bind-task-x11.cabal
+++ b/wild-bind-task-x11.cabal
@@ -1,5 +1,5 @@
 name:                   wild-bind-task-x11
-version:                0.1.0.1
+version:                0.2.0.0
 author:                 Toshio Ito <debug.ito@gmail.com>
 maintainer:             Toshio Ito <debug.ito@gmail.com>
 license:                BSD3
@@ -17,13 +17,13 @@
   default-language:     Haskell2010
   hs-source-dirs:       src
   ghc-options:          -Wall -fno-warn-unused-imports
-  default-extensions:   OverloadedStrings
-  exposed-modules:      WildBind.Task.X11
+  exposed-modules:      WildBind.Task.X11,
+                        WildBind.Task.X11.Seq.Example
   -- other-modules:
   build-depends:        base >=4.6 && <5.0,
                         wild-bind >=0.1.0 && <0.2,
-                        wild-bind-x11 >=0.1.0 && <0.2,
-                        wild-bind-indicator >=0.1.0 && <0.2,
+                        wild-bind-x11 >=0.1.0 && <0.3,
+                        wild-bind-indicator >=0.1.0 && <0.3,
                         text >=1.2.0 && <1.3,
                         transformers >=0.3.0 && <0.6