diff --git a/README.md b/README.md
index 7656d3e..9a0e8fe 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,10 @@ Haskell library and terminal GUI tool for time tracking.
 
     cabal run t4
 
+## Run t4 TUI (t5)
+
+    cabal run t5
+
 ## Run tests
 
     cabal test --test-show-details=direct
diff --git a/lib/T4/Data.hs b/lib/T4/Data.hs
index 5bd7dc2..501dc02 100644
--- a/lib/T4/Data.hs
+++ b/lib/T4/Data.hs
@@ -63,8 +63,8 @@ getDay :: Clock -> Day
 getDay = localDay . getLocalTime . time
 
 summary :: Clock -> String
-summary (Out t)       = "out (" ++ sltString t ++ ")"
-summary (In t mc ts)  = "in (" ++ sltString t ++ ")" ++ catStr ++ tagsStr
+summary (Out t)       = "OUT (" ++ sltString t ++ ")"
+summary (In t mc ts)  = "IN (" ++ sltString t ++ ")" ++ catStr ++ tagsStr
   where catStr  = maybe "" ((" [" ++) . (++ "]")) mc
         tagsStr = concatMap (" #" ++) ts
 
diff --git a/t4-tui/TUI.hs b/t4-tui/TUI.hs
new file mode 100644
index 0000000..405e44b
--- /dev/null
+++ b/t4-tui/TUI.hs
@@ -0,0 +1,86 @@
+module Main where
+
+import T4.Data
+import T4.Storage
+import Util
+import Data.Time
+import Brick
+import Brick.BChan
+import Brick.Widgets.Border
+import Graphics.Vty
+import Lens.Micro.Platform
+import Control.Monad
+import Control.Monad.IO.Class
+import Control.Concurrent
+import System.Process
+
+data Tick = Tick
+            deriving Show
+
+data T4State = T4State
+  { _dir      :: FilePath
+  , _clocks   :: [Clock]
+  , _now      :: SimpleLocalTime
+  , _durConf  :: DurationConfig
+  } deriving Show
+makeLenses ''T4State
+
+main :: IO ()
+main = do
+
+  -- Prepare initial state
+  dd    <- getStorageDirectory
+  curr  <- getCurrentSLT
+  let initState = T4State dd [] curr manDurationConfig
+
+  -- Prepare ticking thread
+  tickChan      <- newBChan 42
+  tickThreadID  <- forkIO $ forever $ do  writeBChan tickChan Tick
+                                          threadDelay $ 1000 * 1000 -- 1 sec.
+  -- Go
+  void $ customMainWithDefaultVty (Just tickChan) t4App initState
+
+  -- Cleanup
+  callCommand "clear"
+  killThread tickThreadID
+
+t4App :: App T4State Tick ()
+t4App = App
+  { appDraw         = drawT4
+  , appChooseCursor = neverShowCursor
+  , appHandleEvent  = handleEvent
+  , appStartEvent   = initT4
+  , appAttrMap      = const $ attrMap defAttr []
+  }
+
+initT4 :: EventM () T4State ()
+initT4 = do
+  loadedClocks <- liftIO . loadDataFromDir =<< use dir
+  clocks .= loadedClocks
+
+drawT4 :: T4State -> [Widget ()]
+drawT4 state = [ui]
+  where ui = hBox [ box (lastClock (state^.clocks^?_last))
+                  , fill ' '
+                  , box (duration (state^.durConf) durPair)
+                  ]
+        durPair = do  c1 <- state^.clocks^?_last
+                      guard $ isIn c1
+                      let t1 = getLocalTime $ time c1
+                          t2 = getLocalTime $ state^.now
+                      return $ diffLocalTime t2 t1
+        box     = border . padLeftRight 2
+
+lastClock :: Maybe Clock -> Widget ()
+lastClock = str . maybe "no data" summary
+
+duration :: DurationConfig -> Maybe NominalDiffTime -> Widget ()
+duration dc = str . maybe "Not clocked in" (showDiffTime dc)
+
+handleEvent :: BrickEvent () Tick -> EventM () T4State ()
+handleEvent (AppEvent Tick) = do
+  c <- liftIO getCurrentSLT
+  now .= c
+  return ()
+handleEvent (VtyEvent (EvKey KEsc []))  = halt
+handleEvent e                           = liftIO $ print e
diff --git a/terminal-time-tracking-tool.cabal b/terminal-time-tracking-tool.cabal
index 3bcc1ba..15d8623 100644
--- a/terminal-time-tracking-tool.cabal
+++ b/terminal-time-tracking-tool.cabal
@@ -32,7 +32,6 @@ common basics
                     , yaml
                     , regex-tdfa
                     , text
-                    , brick
 
 library
   import:             basics
@@ -51,6 +50,17 @@ executable t4
   hs-source-dirs:     t4-commands
   main-is:            Commands.hs
 
+executable t5
+  import:             basics
+  ghc-options:        -threaded
+  build-depends:      terminal-time-tracking-tool
+                    , vty
+                    , brick
+                    , microlens-platform
+                    , process
+  hs-source-dirs:     t4-tui
+  main-is:            TUI.hs
+
 test-suite t4-test
   import:             basics
   ghc-options:        -Wno-orphans
diff --git a/test/T4/DataSpec.hs b/test/T4/DataSpec.hs
index 983f909..9c21af1 100644
--- a/test/T4/DataSpec.hs
+++ b/test/T4/DataSpec.hs
@@ -82,11 +82,11 @@ spec = do
 
     context "Summary: stringification for humans" $ do
       it "Simple clock in" $
-        summary cIn `shouldBe` "in (2017-11-23 17:42:37) [foo] #bar #baz"
+        summary cIn `shouldBe` "IN (2017-11-23 17:42:37) [foo] #bar #baz"
       it "Clock in without category" $
-        summary cInNoCat `shouldBe` "in (2017-11-23 17:42:37) #bar #baz"
+        summary cInNoCat `shouldBe` "IN (2017-11-23 17:42:37) #bar #baz"
       it "Clock out" $
-        summary cOut `shouldBe` "out (2017-11-23 17:42:37)"
+        summary cOut `shouldBe` "OUT (2017-11-23 17:42:37)"
 
     context "YAML clock data" $ do
       it "Reading simple clock-in data" $