diff --git a/Assets/test/QRCode.mat b/Assets/test/QRCode.mat
index 68b50ec..c9b6cac 100644
--- a/Assets/test/QRCode.mat
+++ b/Assets/test/QRCode.mat
@@ -77,7 +77,9 @@ Material:
     - _SmoothnessTextureChannel: 0
     - _SpecularHighlights: 1
     - _SrcBlend: 1
+    - _TimeSlider: 0
     - _UVSec: 0
+    - _Version: 1
     - _ZWrite: 1
     m_Colors:
     - _Color: {r: 1, g: 1, b: 1, a: 1}
diff --git a/Assets/test/QRCode.shader b/Assets/test/QRCode.shader
index a03269c..3645021 100644
--- a/Assets/test/QRCode.shader
+++ b/Assets/test/QRCode.shader
@@ -1,8 +1,9 @@
 Shader "CrispyPin/QRCode" {
 Properties {
 	[HideInInspector]
-	_("",2D)=""
-	_Version("Version", Integer) = 1
+	_("",2D)=""{}
+	_Version("Version", Range(1, 40)) = 1
+	_TimeSlider("Time", Range(0, 250)) = 0
 }
 SubShader {
 Tags { "RenderType"="Opaque" }
@@ -11,13 +12,19 @@ CGPROGRAM
 	#pragma surface s Standard
 	struct Input{float2 uv_;};
 	uint _Version;
+	float _TimeSlider;
 
 	#define VERSION _Version
 	#define WIDTH (17 + VERSION * 4)
+	#define PIXEL_WIDTH WIDTH
+	// #define PIXEL_WIDTH 177
 	#define ALIGNERS ((VERSION / 7) + 2)
 	#define ALIGNER_SPACING_IDEAL ((WIDTH - 13) / (ALIGNERS-1))
 	#define ALIGNER_SPACING (ALIGNER_SPACING_IDEAL + ALIGNER_SPACING_IDEAL % 2)
 	#define MISALIGNMENT ((WIDTH - 13) - ALIGNER_SPACING * ALIGNERS)
+	#define BIT_COUNT (WIDTH * WIDTH - 225 - (WIDTH - 17)*2)
+	#define TIME (_Time.y*24)
+	// #define TIME (uint)(_TimeSlider)
 
 	#define EC_LEVEL_L 1
 	#define EC_LEVEL_M 0
@@ -40,24 +47,24 @@ CGPROGRAM
 
 	#define WHITE 1
 	#define BLACK 0
-	#define PINK float4(1, .3, .5, 1)
-	#define BLUE float4(0, .4, .7, 1)
+	#define PINK float3(1, .3, .5)
+	#define BLUE float3(0, .4, .7)
+	#define CYAN float3(0,1,1)
 
-	float4 finder_pattern(uint x, uint y) {
+	float3 finder_pattern(uint x, uint y) {
 		if (x < 6 && x > 0 && y < 6 && y > 0) return !(x < 5 && x > 1 && y < 5 && y > 1);
 		return (x > 6 || y > 6);
 	}
 
-	float4 main (float2 uv){
+	float3 main (float2 uv){
 		const uint data[] = {0x68656c6c,0x6f20776f,0x726c6421};
 		uv.y = 1 - uv.y;
 		uv = uv * 1.5 - 0.25;
 		// Quiet zone
 		if (uv.x < 0 || uv.x > 1 || uv.y < 0 || uv.y > 1) return 1;
 
-		uint px = uv.x * WIDTH;
-		uint py = uv.y * WIDTH;
-
+		uint px = uv.x * PIXEL_WIDTH;
+		uint py = uv.y * PIXEL_WIDTH;
 
 		// Finder patterns
 		if (px < 8 && py < 8) return finder_pattern(px, py);
@@ -77,14 +84,14 @@ CGPROGRAM
 			&& (px < WIDTH - 13 || py > 12) // top right
 			&& (py < WIDTH - 13 || px > 12) // bottom left
 			) {
-			uint x = px + ALIGNER_SPACING - 4 - MISALIGNMENT;
-			uint y = py + ALIGNER_SPACING - 4 - MISALIGNMENT;
-			if (px < 15) x += MISALIGNMENT;
-			if (py < 15) y += MISALIGNMENT;
-			uint ax = x % ALIGNER_SPACING;
-			uint ay = y % ALIGNER_SPACING;
-			if (ax < 5 && ay < 5) {
-				return (ax < 4 && ax > 0 && ay < 4 && ay > 0 && !(ax == 2 && ay == 2));
+			uint x = px + ALIGNER_SPACING - 4;
+			uint y = py + ALIGNER_SPACING - 4;
+			if (px > 12) x -= MISALIGNMENT;
+			if (py > 12) y -= MISALIGNMENT;
+			x %= ALIGNER_SPACING;
+			y %= ALIGNER_SPACING;
+			if (x < 5 && y < 5) {
+				return (x < 4 && x > 0 && y < 4 && y > 0 && !(x == 2 && y == 2));
 			}
 		}
 
@@ -100,11 +107,38 @@ CGPROGRAM
 		// bottom
 		if (px == 8 && py > WIDTH - 8) return (FORMAT_BITS & (1 << py + 15 - WIDTH)) == 0;
 
-		uint column = (WIDTH - px - (px > 6))/2;
-		uint direction_up = column & 1;
+		// data bit layout
+		uint column = (WIDTH - px - (px < 6)-1)/2;
+		uint direction_up = column % 2 == 0;
+		uint full_columns = column > 4 ? column - 4 : 0;
+		full_columns = min(full_columns, VERSION*2);
+		// the 4 columns under the right finder
+		uint short_columns = min(column, 4);
+		// between the left two finder patterns
+		uint tiny_columns = column > (VERSION*2 + 4) ? column - (VERSION*2 + 4) : 0;
+		uint bit_index = full_columns * (WIDTH - 1) * 2;
+		bit_index += short_columns * (WIDTH - 9) * 2;
+		bit_index += tiny_columns * (WIDTH - 17) * 2;
+		bit_index += (px + (px < 6)) % 2;
+
+		if (direction_up) {
+			bit_index += (WIDTH - py - 1 - (py < 7)) * 2;
+		} else {// direction down
+			const uint diff = (full_columns == 0) ? 9 : (py > 6);
+			bit_index += (py - diff)*2;
+		}
+		if (px < 9)	bit_index -= 16; // rightmost tiny column
+
+		// debugging worm
+		uint worm = abs(TIME % BIT_COUNT - bit_index);
+		const uint length = 4;
+		if (worm < length) return CYAN * (worm/(float)length);
+		return (float)(bit_index%BIT_COUNT)/(float)BIT_COUNT;
+
 		// return lerp(BLUE, PINK, column / (WIDTH/2.));
 		return lerp(BLUE, PINK, (px+py)&1);
-		// return float4((px/8 + py/8) & 1, (px/2 + py/2) & 1, (px/4 + py/4) & 1, 1);
+		// return float3((px%5)/5., (px/10+py/10)&1, (py%5)/5.);
+		// return float3((px/8 + py/8) & 1, (px/2 + py/2) & 1, (px/4 + py/4) & 1, 1);
 		// return direction_up;
 		return 0.5;
 	}
diff --git a/Assets/test/TestProps.unity b/Assets/test/TestProps.unity
index 982416b..e6c90d1 100644
--- a/Assets/test/TestProps.unity
+++ b/Assets/test/TestProps.unity
@@ -1360,7 +1360,7 @@ Transform:
   m_PrefabAsset: {fileID: 0}
   m_GameObject: {fileID: 1500710831}
   m_LocalRotation: {x: 0, y: 1, z: 0, w: 0}
-  m_LocalPosition: {x: 0, y: 0.45, z: 1}
+  m_LocalPosition: {x: 0, y: 1, z: 1}
   m_LocalScale: {x: 1, y: 1, z: 1}
   m_ConstrainProportionsScale: 0
   m_Children: []