diff --git a/shader/.wallShadow.frag.swp b/shader/.wallShadow.frag.swp
new file mode 100644
index 000000000..bb5e04a6d
Binary files /dev/null and b/shader/.wallShadow.frag.swp differ
diff --git a/shader/.wallShadow.geom.swp b/shader/.wallShadow.geom.swp
new file mode 100644
index 000000000..82feeac23
Binary files /dev/null and b/shader/.wallShadow.geom.swp differ
diff --git a/shader/wallShadow.frag b/shader/wallShadow.frag
new file mode 100644
index 000000000..e8c6b5aca
--- /dev/null
+++ b/shader/wallShadow.frag
@@ -0,0 +1,7 @@
+#version 430 core
+out vec4 fColor;
+
+void main()
+{
+  fColor = vec4 (0.9,0.9,0,1);
+}
diff --git a/shader/wallShadow.geom b/shader/wallShadow.geom
new file mode 100644
index 000000000..7c248e807
--- /dev/null
+++ b/shader/wallShadow.geom
@@ -0,0 +1,26 @@
+#version 430 core
+layout (points) in;
+layout (triangle_strip, max_vertices = 4) out;
+
+in vec4 vBackPoss[];
+uniform vec2 lightPos;
+
+void main()
+{
+  vec2 posa = gl_in[0].gl_Position.xy;
+  vec2 posb = gl_in[0].gl_Position.zw;
+  vec2 v = normalize( posb - posa);
+  vec2 off = vec2( -(v.y *0.2) 
+                 , v.x *0.2 );
+
+  gl_Position = vec4 (posa, 0 , 1);
+  EmitVertex();
+  gl_Position = vec4 (posb, 0 , 1);
+  EmitVertex();
+  gl_Position = vec4 (posa + off, 0 , 1);
+  EmitVertex();
+  gl_Position = vec4 (posb + off, 0 , 1);
+  EmitVertex();
+
+  EndPrimitive();
+}
diff --git a/shader/wallShadow.vert b/shader/wallShadow.vert
new file mode 100644
index 000000000..731d182aa
--- /dev/null
+++ b/shader/wallShadow.vert
@@ -0,0 +1,11 @@
+#version 430 core
+layout (location = 0) in vec4 poss;
+layout (location = 1) in vec4 backPoss;
+
+out vec4 vBackPoss;
+
+void main()
+{
+  gl_Position = poss;
+  vBackPoss = backPoss;
+}
diff --git a/src/Picture/Preload.hs b/src/Picture/Preload.hs
index 91cc7d6c3..7be31c4c7 100644
--- a/src/Picture/Preload.hs
+++ b/src/Picture/Preload.hs
@@ -25,12 +25,14 @@ data PreloadData = PreloadData
     , _arcShader  :: Program
     , _fadeCircleShader :: Program
     , _backShader :: Program
+    , _wallShadowShader :: Program
     , _triVAO :: VAO
     , _lineVAO :: VAO
     , _textVAO :: VAO
     , _circVAO :: VAO
     , _arcVAO  :: VAO
     , _backVAO :: VAO
+    , _wallVAO :: VAO
     , _posVBO :: BufferObject
     , _colVBO :: BufferObject
     , _texVBO :: BufferObject
@@ -103,11 +105,13 @@ doPreload' = do
     as <- makeArcShader
     fcs <- makeFadeShader
     bgs <- makeBackgroundShader
+    wss <- makeWallShadowShader
 
     winSizeUni <- GL.uniformLocation cs "winSize"
     zoomUni    <- GL.uniformLocation cs "zoom"
     asWinSizeUniLoc <- GL.uniformLocation as "winSize"
     asZoomUniLoc    <- GL.uniformLocation as "zoom"
+    wssLightPosUniLoc   <- GL.uniformLocation wss "lightPos"
 -- get uniform locations
 
 --setup vbos
@@ -159,6 +163,7 @@ doPreload' = do
     circvao <- setupVAO [(posVBO,0,3),(colVBO,1,4),(texVBO,2,1)]
     arcvao  <- setupVAO [(posVBO,0,3),(colVBO,1,4),(texVBO,2,4)]
     backgroundvao <- setupVAO [(posVBO,0,4),(colVBO,1,2)]
+    wallvao <- setupVAO [(posVBO,0,4),(colVBO,1,4)]
     
     return $ PreloadData
         { -- _charMap      = convertRGBA8 cmap
@@ -169,12 +174,14 @@ doPreload' = do
         , _arcShader = as
         , _fadeCircleShader = fcs
         , _backShader = bgs
+        , _wallShadowShader = wss
         , _triVAO  = trivao
         , _textVAO = textvao
         , _circVAO = circvao
         , _arcVAO  = arcvao
         , _lineVAO = linevao
         , _backVAO = backgroundvao
+        , _wallVAO = wallvao
         , _posVBO = posVBO
         , _colVBO = colVBO
         , _texVBO = texVBO
diff --git a/src/Shaders.hs b/src/Shaders.hs
index 1cfc7d165..d08a06069 100644
--- a/src/Shaders.hs
+++ b/src/Shaders.hs
@@ -1,14 +1,12 @@
 {-# LANGUAGE QuasiQuotes #-}
 module Shaders 
-    (setupBasicShader
-    ,setupFadeShader
-    ,setupShaders
-    ,makeTextureShader
+    (makeTextureShader
     ,makeBasicShader
     ,makeFadeShader
     ,makeCircleShader
     ,makeArcShader
     ,makeBackgroundShader
+    ,makeWallShadowShader
     )
     where
 import Graphics.Rendering.OpenGL
@@ -16,13 +14,6 @@ import Control.Monad (when)
 import Text.RawString.QQ
 import qualified Data.ByteString as BS
 
-setupShaders :: IO [Program]
-setupShaders = do
-    basicShader <- makeBasicShader
-    fadeShader <- makeFadeShader
-    textureShader <- makeTextureShader
-    return [basicShader,fadeShader,textureShader]
-
 makeBasicShader :: IO Program
 makeBasicShader = do
     vsSource <- BS.readFile "shader/basic.vert"
@@ -32,11 +23,6 @@ makeBasicShader = do
                       ,(FragmentShader, fsSource)
                       ]
 
-setupBasicShader :: IO ()
-setupBasicShader = do
-    shaderProgram <- makeBasicShader
-    currentProgram $= (Just shaderProgram)
-
 makeCircleShader :: IO Program
 makeCircleShader = do
     vsSource <- BS.readFile "shader/circle.vert"
@@ -80,11 +66,16 @@ makeBackgroundShader = do
                       ,(FragmentShader, fsSource )
                       ]
 
-setupFadeShader :: IO Program
-setupFadeShader = do
-    shaderProgram <- makeFadeShader
-    currentProgram $= (Just shaderProgram)
-    return shaderProgram
+makeWallShadowShader :: IO Program
+makeWallShadowShader = do
+    vsSource <- BS.readFile "shader/wallShadow.vert"
+    gsSource <- BS.readFile "shader/wallShadow.geom"
+    fsSource <- BS.readFile "shader/wallShadow.frag"
+
+    makeShaderProgram [(VertexShader,   vsSource )
+                      ,(GeometryShader, gsSource )
+                      ,(FragmentShader, fsSource )
+                      ]
 
 makeTextureShader :: IO Program
 makeTextureShader = do