diff --git a/19-shadows/starter/Shadows.playground/Pages/1. Hard Shadows.xcplaygroundpage/Sources/Renderer.swift b/19-shadows/starter/Shadows.playground/Pages/1. Hard Shadows.xcplaygroundpage/Sources/Renderer.swift
index 9b59f12..83783dd 100644
--- a/19-shadows/starter/Shadows.playground/Pages/1. Hard Shadows.xcplaygroundpage/Sources/Renderer.swift	
+++ b/19-shadows/starter/Shadows.playground/Pages/1. Hard Shadows.xcplaygroundpage/Sources/Renderer.swift	
@@ -17,9 +17,7 @@ public class Renderer: NSObject, MTKViewDelegate {
     device = MTLCreateSystemDefaultDevice()
     queue = device!.makeCommandQueue()
     do {
-      guard let path = Bundle.main.path(forResource: "Shaders", ofType: "metal") else { fatalError() }
-      let input = try String(contentsOfFile: path, encoding: String.Encoding.utf8)
-      let library = try device.makeLibrary(source: input, options: nil)
+      let library = device.makeDefaultLibrary()!
       guard let kernel = library.makeFunction(name: "compute") else { fatalError() }
       pipelineState = try device.makeComputePipelineState(function: kernel)
     } catch let e {
diff --git a/19-shadows/starter/Shadows.playground/Pages/2. Soft Shadows.xcplaygroundpage/Sources/Renderer.swift b/19-shadows/starter/Shadows.playground/Pages/2. Soft Shadows.xcplaygroundpage/Sources/Renderer.swift
index 67bade9..17a4050 100644
--- a/19-shadows/starter/Shadows.playground/Pages/2. Soft Shadows.xcplaygroundpage/Sources/Renderer.swift	
+++ b/19-shadows/starter/Shadows.playground/Pages/2. Soft Shadows.xcplaygroundpage/Sources/Renderer.swift	
@@ -17,9 +17,7 @@ public class Renderer: NSObject, MTKViewDelegate {
     device = MTLCreateSystemDefaultDevice()
     queue = device!.makeCommandQueue()
     do {
-      guard let path = Bundle.main.path(forResource: "Shaders", ofType: "metal") else { fatalError() }
-      let input = try String(contentsOfFile: path, encoding: String.Encoding.utf8)
-      let library = try device.makeLibrary(source: input, options: nil)
+      let library = device.makeDefaultLibrary()!
       guard let kernel = library.makeFunction(name: "compute") else { fatalError() }
       pipelineState = try device.makeComputePipelineState(function: kernel)
     } catch let e {
diff --git a/19-shadows/starter/Shadows.playground/Pages/3. Ambient Occlusion.xcplaygroundpage/Sources/Renderer.swift b/19-shadows/starter/Shadows.playground/Pages/3. Ambient Occlusion.xcplaygroundpage/Sources/Renderer.swift
index 67bade9..17a4050 100755
--- a/19-shadows/starter/Shadows.playground/Pages/3. Ambient Occlusion.xcplaygroundpage/Sources/Renderer.swift	
+++ b/19-shadows/starter/Shadows.playground/Pages/3. Ambient Occlusion.xcplaygroundpage/Sources/Renderer.swift	
@@ -17,9 +17,7 @@ public class Renderer: NSObject, MTKViewDelegate {
     device = MTLCreateSystemDefaultDevice()
     queue = device!.makeCommandQueue()
     do {
-      guard let path = Bundle.main.path(forResource: "Shaders", ofType: "metal") else { fatalError() }
-      let input = try String(contentsOfFile: path, encoding: String.Encoding.utf8)
-      let library = try device.makeLibrary(source: input, options: nil)
+      let library = device.makeDefaultLibrary()!
       guard let kernel = library.makeFunction(name: "compute") else { fatalError() }
       pipelineState = try device.makeComputePipelineState(function: kernel)
     } catch let e {