diff --git a/shaders/frag0.glsl b/shaders/frag0.glsl
index ea915e5..df1fe8e 100644
--- a/shaders/frag0.glsl
+++ b/shaders/frag0.glsl
@@ -4,12 +4,14 @@
 // ================================
 
 // 1. real time uniforms
+// ---------------------
 
 uniform float iTime;
 uniform float iTempo;
 uniform vec2 iResolution;
 
 // 2. other frames
+// ---------------
 
 uniform sampler2D frame0;
 uniform sampler2D frame1;
@@ -20,15 +22,13 @@ uniform sampler2D frame5;
 uniform sampler2D frame6;
 uniform sampler2D frame7;
 
-// 3. input UV vector
-
-in vec2 vUV;
-
-// 4. definitions
+// 3. definitions
+// --------------
 
 #define PI 3.1415927
 
-// 5. functions
+// 4. functions
+// ------------
 
 // BASICS
 
@@ -785,4 +785,12 @@ int guess_char(sampler2D frame, vec2 uv, float k, float t)
     return mc;
 }
 
-// OTHER
+// 5. generators
+// -------------
+
+// TODO
+
+// 6. effects
+// ----------
+
+// TODO
\ No newline at end of file
diff --git a/shaders/frag1.glsl b/shaders/frag1.glsl
index 275139d..9393752 100644
--- a/shaders/frag1.glsl
+++ b/shaders/frag1.glsl
@@ -3,6 +3,7 @@
 // IN: 0 / 1
 // OUT: 3
 
+in vec2 vUV;
 layout(location = 3) out vec3 fragColor;
 
 void main() {
diff --git a/shaders/frag2.glsl b/shaders/frag2.glsl
index e837aab..3e7f937 100644
--- a/shaders/frag2.glsl
+++ b/shaders/frag2.glsl
@@ -3,6 +3,7 @@
 // IN: 0 / 2
 // OUT: 4
 
+in vec2 vUV;
 layout(location = 4) out vec3 fragColor;
 
 void main() {
diff --git a/shaders/frag3.glsl b/shaders/frag3.glsl
index 0cc2abc..cef7a3f 100644
--- a/shaders/frag3.glsl
+++ b/shaders/frag3.glsl
@@ -3,6 +3,7 @@
 // IN: 3 / 5
 // OUT: 5
 
+in vec2 vUV;
 layout(location = 5) out vec3 fragColor;
 
 void main() {
diff --git a/shaders/frag4.glsl b/shaders/frag4.glsl
index d84de33..c5ae4e8 100644
--- a/shaders/frag4.glsl
+++ b/shaders/frag4.glsl
@@ -3,6 +3,7 @@
 // IN: 4 / 6
 // OUT: 6
 
+in vec2 vUV;
 layout(location = 6) out vec3 fragColor;
 
 void main() {
diff --git a/shaders/frag5.glsl b/shaders/frag5.glsl
index 6d21a45..e54a200 100644
--- a/shaders/frag5.glsl
+++ b/shaders/frag5.glsl
@@ -3,6 +3,7 @@
 // IN: 5 / 6
 // OUT: 7
 
+in vec2 vUV;
 layout(location = 7) out vec3 fragColor;
 
 void main() {
diff --git a/shaders/frag6.glsl b/shaders/frag6.glsl
index 91dae75..d494e80 100644
--- a/shaders/frag6.glsl
+++ b/shaders/frag6.glsl
@@ -3,6 +3,7 @@
 // IN: 7 / 0
 // OUT: 0
 
+in vec2 vUV;
 layout(location = 0) out vec3 fragColor;
 
 void main() {