diff --git a/gluturtle.cabal b/gluturtle.cabal
--- a/gluturtle.cabal
+++ b/gluturtle.cabal
@@ -2,7 +2,7 @@
 cabal-version:	>= 1.6
 
 name:		gluturtle
-version:	0.0.3
+version:	0.0.4
 stability:	alpha
 author:		Yoshikuni Jujo <PAF01143@nifty.ne.jp>
 maintainer:	Yoshikuni Jujo <PAF01143@nifty.ne.jp>
@@ -29,6 +29,7 @@
   Other-modules:	Graphics.UI.GLUT.Turtle.Field, Graphics.UI.GLUT.Turtle.Input,
     Graphics.UI.GLUT.Turtle.Move, Graphics.UI.GLUT.Turtle.State,
     Graphics.UI.GLUT.Turtle.Data, Graphics.UI.GLUT.Turtle.Layers
+    Graphics.UI.GLUT.Turtle.Triangles, Graphics.UI.GLUT.Turtle.TriangleTools
 
 executable		testTurtle
   Hs-source-dirs:	tests, src
diff --git a/src/Graphics/UI/GLUT/Turtle/Field.hs b/src/Graphics/UI/GLUT/Turtle/Field.hs
--- a/src/Graphics/UI/GLUT/Turtle/Field.hs
+++ b/src/Graphics/UI/GLUT/Turtle/Field.hs
@@ -52,6 +52,8 @@
 import System.Exit
 import Control.Applicative
 
+import Graphics.UI.GLUT.Turtle.Triangles
+
 import Graphics.UI.GLUT(
 	createWindow, Vertex2(..), renderPrimitive, vertex, PrimitiveMode(..),
 	preservingMatrix, GLfloat, swapBuffers, ($=), displayCallback,
@@ -110,8 +112,8 @@
 	layers <- newLayers 0 (return ()) (return ()) (return ())
 	action <- newIORef $ return ()
 	actions <- newIORef []
-	str <- newIORef "coi rodo"
-	str2 <- newIORef "hello"
+	str <- newIORef ""
+	str2 <- newIORef "coi rodo"
 	inputtext <- newIORef $ const $ return True
 
 	initialDisplayMode $= [RGBMode, DoubleBuffered]
@@ -242,11 +244,30 @@
 colorToColor4 (RGB r g b) = G.Color4
 	(fromIntegral r / 255) (fromIntegral g / 255) (fromIntegral b / 255) 0
 
-makeCharacterAction :: [Position] -> IO ()
-makeCharacterAction ps =
+makeCharacterAction :: [Position] -> Color -> Color -> Double -> IO ()
+makeCharacterAction ps c lc lw =
 	preservingMatrix $ do
-		renderPrimitive Polygon $ mapM_ (vertex . positionToVertex3) ps
+		print ps
+		G.color $ colorToColor4 c
+		renderPrimitive Triangles $ mapM_ (vertex . positionToVertex3) $
+			map posToPosition $ triangleToPositions $
+			toTriangles $ map positionToPos ps
+--		renderPrimitive Polygon $ mapM_ (vertex . positionToVertex3) ps
+		G.lineWidth $= fromRational (toRational lw)
+		G.color $ colorToColor4 lc
+		renderPrimitive LineLoop $ mapM_ (vertex . positionToVertex3) ps
 
+type Pos = (Double, Double)
+triangleToPositions :: [(Pos, Pos, Pos)] -> [Pos]
+triangleToPositions [] = []
+triangleToPositions ((a, b, c) : rest) = a : b : c : triangleToPositions rest
+
+positionToPos :: Position -> Pos
+positionToPos (Center x y) = (x, y)
+
+posToPosition :: Pos -> Position
+posToPosition (x, y) = Center x y
+
 positionToVertex3 :: Position -> Vertex2 GLfloat
 positionToVertex3 (Center x y) =
 	Vertex2 (fromRational $ toRational x / 300)
@@ -264,7 +285,7 @@
 
 fillPolygon :: Field -> Layer -> [Position] -> Color -> Color -> Double -> IO ()
 fillPolygon f l ps clr lc lw = do
-	atomicModifyIORef_ (fActions f) (makeCharacterAction ps :)
+	atomicModifyIORef_ (fActions f) (makeCharacterAction ps clr lc lw :)
 
 --------------------------------------------------------------------------------
 
@@ -276,7 +297,7 @@
 drawCharacterAndLine f ch fclr clr sh lw p q =
 	writeIORef (fAction f) $ do
 		makeLineAction p q clr lw
-		makeCharacterAction sh
+		makeCharacterAction sh fclr clr lw
 
 clearCharacter :: Character -> IO ()
 clearCharacter ch = character ch $ return ()
@@ -309,7 +330,8 @@
 	($ str) =<< readIORef (fInputtext f)
 	writeIORef (fString2 f) str
 	writeIORef (fString f) ""
+keyboardProc f (G.Char '\b') G.Down _ _ = atomicModifyIORef_ (fString f) init
 keyboardProc f (G.Char c) state _ _
-	| state == G.Down = atomicModifyIORef_ (fString f) (++ [c])
+	| state == G.Down = print c >> atomicModifyIORef_ (fString f) (++ [c])
 	| otherwise = return ()
 keyboardProc _ _ _ _ _ = return ()
diff --git a/src/Graphics/UI/GLUT/Turtle/TriangleTools.hs b/src/Graphics/UI/GLUT/Turtle/TriangleTools.hs
new file mode 100644
--- /dev/null
+++ b/src/Graphics/UI/GLUT/Turtle/TriangleTools.hs
@@ -0,0 +1,186 @@
+module Graphics.UI.GLUT.Turtle.TriangleTools (
+	Pos,
+	far,
+--	maximumIndex,
+--	distance2,
+	index3,
+	deleteIndex,
+
+	distant3,
+	within,
+	isRight,
+	online,
+	deleteOnline,
+	draw,
+
+	pa, pb, pc, pd, pe
+) where
+
+import Graphics.UI.GLUT
+import System.Environment
+
+far :: [Pos] -> Int
+far = maximumIndex . map distance2
+
+deleteOnline xs = init $ tail $ dol $ last xs : xs ++ [head xs]
+
+dol :: [Pos] -> [Pos]
+dol [a, b] = [a, b]
+dol (a : ps@(b : ps'@(c : _)))
+	| online (a, b, c) = a : dol ps'
+	| otherwise = a : dol ps
+
+maximumIndex :: Ord a => [a] -> Int
+maximumIndex = fst . maximumIndexGen
+
+index3 :: [a] -> Int -> (a, a, a)
+index3 xs i = (xs' !! i, xs' !! (i + 1), xs' !! (i + 2))
+	where
+	xs' = last xs : xs ++ [head xs]
+
+deleteIndex :: [a] -> Int -> [a]
+deleteIndex xs i = take i xs ++ drop (i + 1) xs
+
+maximumIndexGen :: Ord a => [a] -> (Int, a)
+maximumIndexGen [x] = (0, x)
+maximumIndexGen (x : xs)
+	| x >= x' = (0, x)
+	| otherwise = (i + 1, x')
+	where
+	(i, x') = maximumIndexGen xs
+
+draw pl trs = do
+	prgName <- getProgName
+	rawArgs <- getArgs
+	args <- initialize prgName rawArgs
+	createWindow "GLTest"
+	displayCallback $= do
+		color $ (Color4 1 1 1 0 :: Color4 GLfloat)
+		drawTriangles trs -- [((50, 50), (-50, -50), (0, 50))]
+		color $ (Color4 1 0 0 0 :: Color4 GLfloat)
+		drawPolyline pl -- [(50, 50), (-50, -50), (0, 50), (-50, 80)]
+		swapBuffers
+		flush
+	mainLoop
+
+main = do
+	prgName <- getProgName
+	rawArgs <- getArgs
+	args <- initialize prgName rawArgs
+	createWindow "GLTest"
+	displayCallback $= displayScene
+	mainLoop
+
+displayScene = do
+--	drawTriangles [(50, 50), (-50, -50), (0, 50)]
+	drawPolyline [(50, 50), (-50, -50), (0, 50), (-50, 80)]
+	swapBuffers
+	flush
+
+drawObject = preservingMatrix $
+	renderPrimitive Lines $ mapM_ vertex [
+		Vertex2 (-0.5) (-0.5),
+		Vertex2 0.5 0.5 :: Vertex2 GLfloat ]
+
+drawTriangles ps = preservingMatrix $
+	renderPrimitive Triangles $ mapM_ vertex $ trianglesToVertex2 ps
+
+trianglesToVertex2 :: [(Pos, Pos, Pos)] -> [Vertex2 GLfloat]
+trianglesToVertex2 [] = []
+trianglesToVertex2 ((a, b, c) : rest) =
+	toVertex2 a : toVertex2 b : toVertex2 c : trianglesToVertex2 rest
+
+toVertex2 :: (Double, Double) -> Vertex2 GLfloat
+toVertex2 (x, y) = Vertex2
+	(fromRational $ toRational x / 20) (fromRational $ toRational y / 20)
+
+drawPolyline ps = preservingMatrix $
+	renderPrimitive LineLoop $ mapM_ (vertex . toVertex2) ps
+
+type Pos = (Double, Double)
+
+isRight :: (Pos, Pos, Pos) -> Bool
+isRight ((xa, ya), (xb, yb), (xc, yc))
+	| 0 < xd * ye - xe * yd = True
+	| 0 == xd * ye - xe * yd = error "bad triangle"
+	| otherwise = False
+	where
+	(xd, yd) = (xa - xb, ya - yb)
+	(xe, ye) = (xc - xb, yc - yb)
+
+distance2 (x, y) = x ** 2 + y ** 2
+
+maximum3 :: Ord a => [a] -> (a, a, a)
+maximum3 xs = maximum3Gen $ last xs : xs ++ [head xs]
+
+maximum3Gen :: Ord a => [a] -> (a, a, a)
+maximum3Gen [x, y, z] = (x, y, z)
+maximum3Gen (x : xs@(y : z : _))
+	| y > y' = (x, y, z)
+	| otherwise = p
+	where
+	p@(x', y', z') = maximum3Gen xs
+
+maximumby3 :: Ord b => (a -> b) -> [a] -> (a, a, a)
+maximumby3 b xs = maximumby3Gen b $ last xs : xs ++ [head xs]
+
+maximumby3Gen :: Ord b => (a -> b) -> [a] -> (a, a, a)
+maximumby3Gen _ [x, y, z] = (x, y, z)
+maximumby3Gen b (x : xs@(y : z : _))
+	| b y > b y' = (x, y, z)
+	| otherwise = p
+	where
+	p@(_, y', _) = maximumby3Gen b xs
+
+maximumby32 b xs = maximumby3Gen2 b $ last xs : xs ++ [head xs]
+
+maximumby3Gen2 :: Ord b => (a -> b) -> [a] -> ((a, a, a), [a])
+maximumby3Gen2 _ [x, y, z] = ((x, y, z), [x, z])
+maximumby3Gen2 b (x : ys@(y : (zs@(z : _))))
+	| b y > b y' = ((x, y, z), x : zs)
+	| otherwise = (t, x : ps)
+	where
+	(t@(_, y', _), ps) = maximumby3Gen2 b ys
+
+distant3 :: [Pos] -> ((Pos, Pos, Pos), [Pos])
+distant3 ps = let (t, ps') = maximumby32 distance2 ps in (t, init $ tail ps')
+
+within :: (Pos, Pos, Pos) -> Pos -> Bool
+within (a, b, c) d
+	| online (d, a, b) || online (d, b, c) || online (d, c, a) = False
+	| otherwise = isRight (a, b, c) &&
+		isRight (d, a, b) && isRight (d, b, c) && isRight (d, c, a)
+
+online :: (Pos, Pos, Pos) -> Bool
+online ((xa, ya), (xb, yb), (xc, yc)) = 0 == xd * ye - xe * yd
+	where
+	(xd, yd) = (xa - xb, ya - yb)
+	(xe, ye) = (xc - xb, yc - yb)
+
+deleteOnlineGen :: (Pos, Pos, Pos) -> (Pos, Pos)
+deleteOnlineGen (p1@(x1, _), p2@(x2, _), p3@(x3, _))
+	| not $ online (p1, p2, p3) = error "not online"
+	| x1 > x3 = deleteOnlineGen (p3, p2, p1)
+	| x2 < x1 = (p2, p3)
+	| x1 <=x2 && x2 <= x3 = (p1, p3)
+	| x3 < x2 = (p1, p2)
+
+pa, pb, pc, pd, pe :: Pos
+pa = (0, 4)
+pb = (4, 4)
+pc = (4, 0)
+pd = (3, 3)
+pe = (2, 2)
+
+{-
+deleteOnline :: [Pos] -> [Pos]
+deleteOnline xs = deleteOnline' $ last xs : xs ++ [head xs]
+
+deleteOnline' :: [Pos] -> [Pos]
+deleteOnline' ps@[_, _] = ps
+deleteOnline' (a : ps@(b : c : ps'))
+	| online (a, b, c) = deleteOnline' $ a' : b' : ps'
+	| otherwise = a : deleteOnline' ps
+	where
+	(a', b') = deleteOnlineGen (a, b, c)
+-}
diff --git a/src/Graphics/UI/GLUT/Turtle/Triangles.hs b/src/Graphics/UI/GLUT/Turtle/Triangles.hs
new file mode 100644
--- /dev/null
+++ b/src/Graphics/UI/GLUT/Turtle/Triangles.hs
@@ -0,0 +1,35 @@
+module Graphics.UI.GLUT.Turtle.Triangles(toTriangles) where
+
+import Graphics.UI.GLUT.Turtle.TriangleTools
+
+ps = [pa, pb, pc, pd]
+ps' = [(1, 3), (2.1, 2), (3, 3.1), (5, 2), (4, 1), (2, 1.5), (1, 1.1)]
+
+main = draw ps' $ toTriangles ps'
+
+toTriangles :: [Pos] -> [(Pos, Pos, Pos)]
+toTriangles ps = toTrianglesTop ps'
+--	| isRight tri = toTrianglesTop ps'
+--	| otherwise = toTrianglesTop $ reverse ps'
+	where
+	ps' = deleteOnline ps
+	(tri, rest) = distant3 ps
+
+toTrianglesTop :: [Pos] -> [(Pos, Pos, Pos)]
+toTrianglesTop [a, b, c] = [(a, b, c)]
+toTrianglesTop ps
+	| any (within tri) ps = toTrianglesNext (isRight tri) i ps
+	| otherwise = tri : toTrianglesTop rest
+	where
+	i = far ps
+	tri = index3 ps i
+	rest = deleteIndex ps i
+
+toTrianglesNext :: Bool -> Int -> [Pos] -> [(Pos, Pos, Pos)]
+toTrianglesNext r i ps
+	| isRight tri /= r || any (within tri) ps = toTrianglesNext r next ps
+	| otherwise = tri : toTrianglesTop rest
+	where
+	tri = index3 ps i
+	rest = deleteIndex ps i
+	next = if i == 0 then length ps - 1 else i - 1
diff --git a/tests/testGLUT.hs b/tests/testGLUT.hs
--- a/tests/testGLUT.hs
+++ b/tests/testGLUT.hs
@@ -12,6 +12,7 @@
 	t <- newTurtle f
 	oninputtext f (processInput t)
 --	speed t "slowest"
+	fillcolor t (255, 255, 255)
 	pencolor t (255, 255, 255)
 --	threadDelay 1000000
 --	left t 45
@@ -27,4 +28,7 @@
 processInput t "bold" = pensize t 3 >> return True
 processInput t "big" = shapesize t 3 3 >> return True
 processInput t "blue" = pencolor t (0, 0, 255) >> return True
+processInput t "fblue" = fillcolor t (0, 0, 255) >> return True
+processInput t "yellow" = pencolor t (255, 255, 0) >> return True
+processInput t "normal" = pensize t 1 >> return True
 processInput t _ = return True