diff --git a/Examples/ObjectiveC/ExtrusionsExample.m b/Examples/ObjectiveC/ExtrusionsExample.m
index 29ef2355..700fb8bf 100644
--- a/Examples/ObjectiveC/ExtrusionsExample.m
+++ b/Examples/ObjectiveC/ExtrusionsExample.m
@@ -7,11 +7,12 @@
 //
 
 #import "ExtrusionsExample.h"
+
 @import Mapbox;
 
 NSString *const MBXExample3DExtrusions = @"ExtrusionsExample";
 
-@interface ExtrusionsExample ()
+@interface ExtrusionsExample () <MGLMapViewDelegate>
 
 @end
 
@@ -19,22 +20,37 @@ @implementation ExtrusionsExample
 
 - (void)viewDidLoad {
     [super viewDidLoad];
-    // Do any additional setup after loading the view.
-}
-
-- (void)didReceiveMemoryWarning {
-    [super didReceiveMemoryWarning];
-    // Dispose of any resources that can be recreated.
+    
+    MGLMapView *mapView = [[MGLMapView alloc] initWithFrame:self.view.bounds styleURL:[MGLStyle lightStyleURLWithVersion:9]];
+    
+    // Center the map on the Colosseum in Rome, Italy.
+    [mapView setCenterCoordinate:CLLocationCoordinate2DMake(41.8902, 12.4922)];
+    
+    // Set the map view camera's pitch and distance.
+    mapView.camera = [MGLMapCamera cameraLookingAtCenterCoordinate:mapView.centerCoordinate fromDistance:600 pitch:60 heading:0];
+    mapView.delegate = self;
+    
+    [self.view addSubview:mapView];
 }
 
-/*
-#pragma mark - Navigation
-
-// In a storyboard-based application, you will often want to do a little preparation before navigation
-- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
-    // Get the new view controller using [segue destinationViewController].
-    // Pass the selected object to the new view controller.
+- (void)mapView:(MGLMapView *)mapView didFinishLoadingStyle:(MGLStyle *)style {
+    
+    // Access the Mapbox Streets source and use it to create a `MGLFillExtrusionLayer`.
+    MGLSource *source = [style sourceWithIdentifier:@"composite"];
+    MGLFillExtrusionStyleLayer *layer = [[MGLFillExtrusionStyleLayer alloc] initWithIdentifier:@"buildings" source:source];
+    layer.sourceLayerIdentifier = @"building";
+    
+    // Filter out buildings that should not extrude.
+    layer.predicate = [NSPredicate predicateWithFormat:@"extrude != false AND height >=0"];
+    
+    // Set the fill extrusion height to the value for the building height attribute.
+    layer.fillExtrusionHeight = [MGLStyleValue valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"height" options:nil];
+    layer.fillExtrusionOpacity = [MGLStyleValue valueWithRawValue:@0.75];
+    layer.fillExtrusionColor = [MGLStyleValue valueWithRawValue:[UIColor whiteColor]];
+    
+    // Insert the fill extrusion layer below a POI label layer.
+    MGLStyleLayer *symbolLayer = [style layerWithIdentifier:@"poi-scalerank3"];
+    [style insertLayer:layer belowLayer:symbolLayer];
 }
-*/
 
 @end
diff --git a/Examples/Swift/ExtrusionsExample.swift b/Examples/Swift/ExtrusionsExample.swift
index b86fcde2..98d02caf 100644
--- a/Examples/Swift/ExtrusionsExample.swift
+++ b/Examples/Swift/ExtrusionsExample.swift
@@ -12,39 +12,39 @@ import Mapbox
 
 class ExtrusionsExample: UIViewController, MGLMapViewDelegate {
     
-    var mapView : MGLMapView!
     override func viewDidLoad() {
         super.viewDidLoad()
         
-        mapView = MGLMapView(frame: view.bounds, styleURL: MGLStyle.lightStyleURL(withVersion: 9))
+        let mapView = MGLMapView(frame: view.bounds, styleURL: MGLStyle.lightStyleURL(withVersion: 9))
+        
+        // Center the map on the Colosseum in Rome, Italy.
         mapView.setCenter(CLLocationCoordinate2D(latitude: 41.8902, longitude: 12.4922), animated: false)
 
-        // Set the `MGLMapCamera` to one
+        // Set the map view camera's pitch and distance.
         mapView.camera = MGLMapCamera(lookingAtCenter: mapView.centerCoordinate, fromDistance: 600, pitch: 60, heading: 0)
-
         mapView.delegate = self
+        
         view.addSubview(mapView)
     }
     
     func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle) {
         
-        // Access the Mapbox Streets source.
+        // Access the Mapbox Streets source and use it to create a `MGLFillExtrusionLayer`.
         let source = style.source(withIdentifier: "composite")
-        
-        // Create a `MGLFillExtrusionLayer` using the building layer from that source.
         let layer = MGLFillExtrusionStyleLayer(identifier: "buildings", source: source!)
         layer.sourceLayerIdentifier = "building"
         
-        // Check that the building is should
+        // Filter out buildings that should not extrude.
         layer.predicate = NSPredicate(format: "extrude != false AND height >=0")
         
+        // Set the fill extrusion height to the value for the building height attribute.
         layer.fillExtrusionHeight = MGLStyleValue(interpolationMode: .identity, sourceStops: nil, attributeName: "height", options: nil)
-        
         layer.fillExtrusionOpacity = MGLStyleValue(rawValue: 0.75)
         layer.fillExtrusionColor = MGLStyleValue(rawValue: .white)
+        
+        // Insert the fill extrusion layer below a POI label layer.
         let symbolLayer = style.layer(withIdentifier: "poi-scalerank3")
         style.insertLayer(layer, below: symbolLayer!)
-        
     }
     
 }