diff --git a/GridLines.shader b/GridLines.shader
index e22720b..848f95e 100644
--- a/GridLines.shader
+++ b/GridLines.shader
@@ -3,28 +3,57 @@ shader_type canvas_item;
 uniform float rows = 44.0;  // Really int but don't want to recast all the time
 uniform float cols = 63.0;  // ^
 
+uniform vec4 color_unmarked: hint_color = vec4(0.5, 0.5, 0.5, 1.0);
+uniform vec4 color_marked: hint_color = vec4(0.0, 0.0, 1.0, 1.0);
+uniform vec4 color_crossed: hint_color = vec4(1.0, 0.0, 0.0, 1.0);
+
+uniform float line_thickness = 0.1;  // Cell scale
+uniform float line_offset = 0.05;  // Should be half of thickness to be centered, but might need tweaking for small values
+
 void fragment(){
 	vec2 frag_pos = UV * vec2(cols, rows);
-	vec2 frag_marginal = fract(frag_pos+0.05);
-	vec2 frag_marginal_2 = fract(frag_pos-0.4);
-	vec2 grid_data = texture(TEXTURE, (frag_pos+0.05)/vec2(cols+1.0, rows+1.0)).rg;
+	bvec2 frag_marginal = lessThan(fract(frag_pos+line_offset), vec2(line_thickness));
+	bvec2 frag_marginal_x = lessThan(fract(frag_pos-0.425), vec2(0.15));
+//	vec2 grid_data = texture(TEXTURE, (frag_pos+line_offset)/vec2(cols+1.0, rows+1.0)).rg;
+//	float grid_data_s = texture(TEXTURE, ((frag_pos+line_offset)/vec2(cols+1.0, rows+1.0)).yx).a*128.0; //*17.0;
+//	COLOR = vec4(grid_data_s, grid_data_s, grid_data_s, 1.0);
+	int grid_data_s = int(texture(TEXTURE, ((frag_pos+line_offset)/vec2(cols+1.0, rows+1.0)).yx).r*255.0);
+	ivec2 grid_data = ivec2(grid_data_s%4, grid_data_s/4);
 	COLOR = vec4(0.0);
-	if (frag_marginal.x < 0.1){
-		if (grid_data.g >= 0.99){
-			if (frag_marginal_2.y <= 0.2)
-				COLOR = vec4(1.0, 0.0, 0.0, 1.0);
-		}else if (grid_data.g >= 0.49){
-			COLOR = vec4(0.0, 0.0, 1.0, 1.0);
+	if (frag_marginal.x){
+		if (grid_data.g >= 2){
+			if (frag_marginal_x.y)
+				COLOR = color_crossed;
+		}else if (grid_data.g == 1){
+			COLOR = color_marked;
 		}else
-			COLOR = vec4(0.5, 0.5, 0.5, 1.0);
+			COLOR = color_unmarked;
 	}
-	if  (frag_marginal.y < 0.1){
-		if (grid_data.r >= 0.99){
-			if (frag_marginal_2.x <= 0.2)
-				COLOR = vec4(1.0, 0.0, 0.0, 1.0);
-		}else if (grid_data.r >= 0.49){
-			COLOR = vec4(0.0, 0.0, 1.0, 1.0);
+	if  (frag_marginal.y){
+		if (grid_data.r >= 2){
+			if (frag_marginal_x.x)
+				COLOR = color_crossed;
+		}else if (grid_data.r == 1){
+			COLOR = color_marked;
 		}else
-			COLOR = vec4(0.5, 0.5, 0.5, 1.0);
+			COLOR = color_unmarked;
 	}
+//	if (frag_marginal.x){
+//		if (grid_data.g >= 0.99){
+//			if (frag_marginal_x.y)
+//				COLOR = color_crossed;
+//		}else if (grid_data.g >= 0.49){
+//			COLOR = color_marked;
+//		}else
+//			COLOR = color_unmarked;
+//	}
+//	if  (frag_marginal.y){
+//		if (grid_data.r >= 0.99){
+//			if (frag_marginal_x.x)
+//				COLOR = color_crossed;
+//		}else if (grid_data.r >= 0.49){
+//			COLOR = color_marked;
+//		}else
+//			COLOR = color_unmarked;
+//	}
 }
\ No newline at end of file
diff --git a/Main.tscn b/Main.tscn
index 6a1f5fe..73a81db 100644
--- a/Main.tscn
+++ b/Main.tscn
@@ -3,10 +3,15 @@
 [ext_resource path="res://scripts/GameField.gd" type="Script" id=1]
 [ext_resource path="res://GridLines.shader" type="Shader" id=2]
 
-[sub_resource type="ShaderMaterial" id=2]
+[sub_resource type="ShaderMaterial" id=1]
 shader = ExtResource( 2 )
 shader_param/rows = 44.0
 shader_param/cols = 63.0
+shader_param/color_unmarked = Color( 0.5, 0.5, 0.5, 1 )
+shader_param/color_marked = Color( 0, 0, 1, 1 )
+shader_param/color_crossed = Color( 1, 0, 0, 1 )
+shader_param/line_thickness = 0.1
+shader_param/line_offset = 0.05
 
 [node name="Control" type="Control"]
 anchor_right = 1.0
@@ -31,7 +36,7 @@ __meta__ = {
 }
 
 [node name="TextureRect" type="TextureRect" parent="GameField"]
-material = SubResource( 2 )
+material = SubResource( 1 )
 margin_top = -2.0
 margin_right = 40.0
 margin_bottom = 38.0
diff --git a/scripts/GameField.gd b/scripts/GameField.gd
index d21f9d0..0f48c9c 100644
--- a/scripts/GameField.gd
+++ b/scripts/GameField.gd
@@ -13,7 +13,7 @@ const IntArray2D = Common.IntArray2D
 onready var cell_numbers: ByteArray2D
 const NUMBER_NONE := 255
 onready var cell_colors: ByteArray2D
-onready var corner_marks: IntArray2D
+onready var corner_marks: ByteArray2D  #IntArray2D
 
 var cell_image := Image.new()
 var cell_texture := ImageTexture.new()
@@ -81,14 +81,15 @@ func regenerate_cell_texture() -> void:
 	cell_texture.create_from_image(cell_image, 0)
 
 func regenerate_grid_texture() -> void:
-#	grid_image.create_from_data(rows, cols, false, Image.FORMAT_R8, cell_corners._array)
-	grid_image.create(cols+1, rows+1, false, Image.FORMAT_RGBA8)
-	grid_image.lock()
-	for row in rows+1:
-		for col in cols+1:
-			var flags = corner_marks.get_cell(row, col)
-			grid_image.set_pixel(col, row, Color(float(flags&3)/2.0, float((flags>>2)&3)/2.0, 0.0))
-	grid_image.unlock()
+	grid_image.create_from_data(rows+1, cols+1, false, Image.FORMAT_L8, corner_marks._array)
+#	grid_image.create(cols+1, rows+1, false, Image.FORMAT_R8)
+#	grid_image.lock()
+#	for row in rows+1:
+#		for col in cols+1:
+#			var flags = corner_marks.get_cell(row, col)
+##			grid_image.set_pixel(col, row, Color(float(flags&3)/2.0, float((flags>>2)&3)/2.0, 0.0))
+#			grid_image.set_pixel(col, row, Color(float(flags&3)/2.0, float((flags>>2)&3)/2.0, 0.0))
+#	grid_image.unlock()
 	grid_texture.create_from_image(grid_image, 0)
 	$TextureRect.set_texture(grid_texture)
 
@@ -180,7 +181,7 @@ func load_puzzle(filename: String):
 	cols = int(file.get_line())
 	cell_numbers = ByteArray2D.new(rows, cols)
 	cell_colors = ByteArray2D.new(rows, cols)
-	corner_marks = IntArray2D.new(rows+1, cols+1, 0)
+	corner_marks = ByteArray2D.new(rows+1, cols+1, 0)
 
 	var row = 0
 	var stage = 0