diff --git a/ch06/chapter06.xcodeproj/project.pbxproj b/ch06/chapter06.xcodeproj/project.pbxproj
index 04ca30b..d317b25 100644
--- a/ch06/chapter06.xcodeproj/project.pbxproj
+++ b/ch06/chapter06.xcodeproj/project.pbxproj
@@ -31,6 +31,16 @@
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		297F43071DEA287400638FC8 /* Supporting files */ = {
+			isa = PBXGroup;
+			children = (
+				298451331D47EF08008D81B9 /* Main.storyboard */,
+				2984513B1D47EF08008D81B9 /* Info.plist */,
+				2984512F1D47EF08008D81B9 /* AppDelegate.swift */,
+			);
+			name = "Supporting files";
+			sourceTree = "<group>";
+		};
 		298451231D47EF07008D81B9 = {
 			isa = PBXGroup;
 			children = (
@@ -51,9 +61,7 @@
 			isa = PBXGroup;
 			children = (
 				298451411D47F0BF008D81B9 /* MetalView.swift */,
-				298451331D47EF08008D81B9 /* Main.storyboard */,
-				2984513B1D47EF08008D81B9 /* Info.plist */,
-				2984512F1D47EF08008D81B9 /* AppDelegate.swift */,
+				297F43071DEA287400638FC8 /* Supporting files */,
 			);
 			path = chapter06;
 			sourceTree = "<group>";
@@ -85,7 +93,7 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0800;
-				LastUpgradeCheck = 0800;
+				LastUpgradeCheck = 0810;
 				ORGANIZATIONNAME = Marius;
 				TargetAttributes = {
 					2984512B1D47EF08008D81B9 = {
@@ -164,8 +172,10 @@
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
@@ -212,8 +222,10 @@
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
diff --git a/ch06/chapter06.xcodeproj/project.xcworkspace/xcuserdata/marius.xcuserdatad/UserInterfaceState.xcuserstate b/ch06/chapter06.xcodeproj/project.xcworkspace/xcuserdata/marius.xcuserdatad/UserInterfaceState.xcuserstate
index 8f4dc11..e1437e6 100644
Binary files a/ch06/chapter06.xcodeproj/project.xcworkspace/xcuserdata/marius.xcuserdatad/UserInterfaceState.xcuserstate and b/ch06/chapter06.xcodeproj/project.xcworkspace/xcuserdata/marius.xcuserdatad/UserInterfaceState.xcuserstate differ
diff --git a/ch06/chapter06.xcodeproj/xcuserdata/marius.xcuserdatad/xcschemes/chapter06.xcscheme b/ch06/chapter06.xcodeproj/xcuserdata/marius.xcuserdatad/xcschemes/chapter06.xcscheme
index af7d21a..ec3e3fb 100644
--- a/ch06/chapter06.xcodeproj/xcuserdata/marius.xcuserdatad/xcschemes/chapter06.xcscheme
+++ b/ch06/chapter06.xcodeproj/xcuserdata/marius.xcuserdatad/xcschemes/chapter06.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0810"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
diff --git a/ch06/chapter06/MetalView.swift b/ch06/chapter06/MetalView.swift
index 58fccb5..8689c5d 100755
--- a/ch06/chapter06/MetalView.swift
+++ b/ch06/chapter06/MetalView.swift
@@ -11,29 +11,25 @@ import UIKit
 class MetalView: UIView {
     
     var commandQueue: MTLCommandQueue!
-    
-    var metalLayer: CAMetalLayer {
-        return self.layer as! CAMetalLayer
-    }
-    
-    override class func layerClass() -> AnyClass {
-        return CAMetalLayer.self
-    }
-    
+    var metalLayer: CAMetalLayer!
+  
     override func didMoveToWindow() {
         super.didMoveToWindow()
-        let device = MTLCreateSystemDefaultDevice()!
-        commandQueue = device.newCommandQueue()
+        metalLayer = CAMetalLayer()
+        metalLayer.device = MTLCreateSystemDefaultDevice()!
+        metalLayer.frame = layer.frame
+        layer.addSublayer(metalLayer)
+        commandQueue = metalLayer.device?.makeCommandQueue()
         redraw()
     }
     
     private func redraw() {
         let drawable = metalLayer.nextDrawable()!
         let descriptor = MTLRenderPassDescriptor()
-        descriptor.colorAttachments[0].clearColor = MTLClearColorMake(0, 1, 1, 1)
+        descriptor.colorAttachments[0].clearColor = MTLClearColorMake(0, 0.5, 0.5, 1)
         descriptor.colorAttachments[0].texture = drawable.texture
-        let commandBuffer = commandQueue.commandBuffer()
-        let commandEncoder = commandBuffer.renderCommandEncoder(with: descriptor)
+        let commandBuffer = commandQueue.makeCommandBuffer()
+        let commandEncoder = commandBuffer.makeRenderCommandEncoder(descriptor: descriptor)
         commandEncoder.endEncoding()
         commandBuffer.present(drawable)
         commandBuffer.commit()