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:	0.0.12
+version:	0.0.13
 stability:	alpha
 author:		Yoshikuni Jujo <PAF01143@nifty.ne.jp>
 maintainer:	Yoshikuni Jujo <PAF01143@nifty.ne.jp>
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
@@ -112,7 +112,7 @@
 openField name w h = do
 	layers <- newLayers 0 (return ()) (return ()) (return ())
 	action <- newIORef $ return ()
-	actions <- newIORef []
+	actions <- newIORef [makeFieldColor $ RGB 255 255 255]
 	str <- newIORef [""]
 	str2 <- newIORef []
 	inputtext <- newIORef $ const $ return True
@@ -198,8 +198,17 @@
 flushField _f _real act = act
 
 fieldColor :: Field -> Layer -> Color -> IO ()
-fieldColor _f _l _clr = return ()
+fieldColor f _l clr =
+	atomicModifyIORef_ (fActions f) ((++ [makeFieldColor clr]) . init)
 
+makeFieldColor clr = preservingMatrix $ do
+	G.color $ colorToColor4 clr
+	renderPrimitive Quads $ mapM_ vertex [
+		G.Vertex2 (-1) (-1),
+		G.Vertex2 (-1) 1,
+		G.Vertex2 1 1,
+		G.Vertex2 1 (-1) :: Vertex2 GLfloat ]
+
 --------------------------------------------------------------------------------
 
 drawLine :: Field -> Layer -> Double -> Color -> Position -> Position -> IO ()
@@ -222,6 +231,13 @@
 	(fromIntegral r / 255) (fromIntegral g / 255) (fromIntegral b / 255) 0
 colorToColor4 _ = error "colorToColor4: not implemented"
 
+makeQuads :: Field -> [Position] -> Color -> IO ()
+makeQuads f ps c =
+	preservingMatrix $ do
+		G.color $ colorToColor4 c
+		renderPrimitive Quads $
+			mapM_ (vertex . positionToVertex3 f) ps
+
 makeCharacterAction :: Field -> [Position] -> Color -> Color -> Double -> IO ()
 makeCharacterAction f ps c lc lw =
 	preservingMatrix $ do
@@ -278,7 +294,11 @@
 drawImage _f _ _fp _pos _w _h = return ()
 
 fillRectangle :: Field -> Layer -> Position -> Double -> Double -> Color -> IO ()
-fillRectangle _f _ _p _w _h _clr = return ()
+fillRectangle f _ p w h clr = do return ()
+{-
+	atomicModifyIORef_ (fActions f) (makeQuads f [
+		Center 0 0, Center 0 100, Center 100 100, Center 100 0] clr])
+-}
 
 fillPolygon :: Field -> Layer -> [Position] -> Color -> Color -> Double -> IO ()
 fillPolygon f _ ps clr lc lw =
diff --git a/tests/testGLUT.hs b/tests/testGLUT.hs
--- a/tests/testGLUT.hs
+++ b/tests/testGLUT.hs
@@ -12,8 +12,8 @@
 	t <- newTurtle f
 	oninputtext f (processInput f t)
 --	speed t "slowest"
-	fillcolor t ((255, 255, 255) :: (Int, Int, Int))
-	pencolor t ((255, 255, 255) :: (Int, Int, Int))
+--	fillcolor t ((255, 255, 255) :: (Int, Int, Int))
+--	pencolor t ((255, 255, 255) :: (Int, Int, Int))
 --	threadDelay 1000000
 --	left t 45
 --	forward t 100
@@ -40,4 +40,6 @@
 processInput _ t "0very1very2very3very4very5very6very7very8very9very0very-long-line"
 	= putStrLn "very long line" >> return True
 processInput _ t "hide" = hideturtle t >> return True
+processInput _ t "bred" = bgcolor t ((255, 0, 0) :: (Int, Int, Int)) >> return True
+processInput _ t "bgreen" = bgcolor t ((0, 255, 0) :: (Int, Int, Int)) >> return True
 processInput _ _ _ = return True