diff --git a/lib/service/engine_service.dart b/lib/service/engine_service.dart
index a76fedb..b276d28 100644
--- a/lib/service/engine_service.dart
+++ b/lib/service/engine_service.dart
@@ -1,4 +1,5 @@
 import 'package:rules_of_living/src/Engine.dart';
+import 'package:rules_of_living/src/Simulation.dart';
 
 class EngineService {
   Engine _uncachedEngineAccess;
@@ -41,18 +42,7 @@ class EngineService {
   int get simSpeed => engine.stepsPerSecond;
   void set simSpeed(int val) => engine.stepsPerSecond = val;
 
-  void reset() {
-    engine.reset();
-  }
-
-  void addRandomPattern() {
-    engine.running = false;
-    engine.addPattern();
-  }
-
-  void clear() {
-    engine.clear();
-  }
-
   bool get isRunning => engine.running;
+
+  void set simulation(Simulation value) => engine.simulation = value;
 }
diff --git a/lib/service/simulation_service.dart b/lib/service/simulation_service.dart
index b5a9021..396290b 100644
--- a/lib/service/simulation_service.dart
+++ b/lib/service/simulation_service.dart
@@ -2,35 +2,42 @@ import 'dart:html' as html;
 import 'dart:math';
 
 import 'package:rules_of_living/service/engine_service.dart';
+import 'package:rules_of_living/src/Simulation.dart';
 
 class SimulationService {
-  final EngineService _engine;
+  // DEFAULT VALUES
+  static final int DEFAULT_GRID_SIZE = 50;
 
-  SimulationService(this._engine);
+  final EngineService _engine;
+  final Simulation _sim = Simulation(DEFAULT_GRID_SIZE, DEFAULT_GRID_SIZE);
+
+  SimulationService(this._engine) {
+    _engine.simulation = _sim;
+    _sim.addRandomPattern(amount: 15, dispersal: 5);
+  }
 
   void reset() {
-    _engine.reset();
+    _sim.reset();
   }
 
   void addRandomPattern() {
-    _engine.addRandomPattern();
+    _sim.addRandomPattern();
   }
 
   void clear() {
-    _engine.clear();
+    _sim.reset();
   }
 
+  Point<int> get gridSize => _sim.gridSize;
   void set gridSize(Point<int> size) {
-    _engine.engine.gridSize = size;
+    _sim.gridSize = size;
   }
 
-  Point<int> get gridSize => _engine.engine.gridSize;
-
   //TODO split into RenderService when rendering is decoupled from engine.
   html.CanvasElement get canvas => _engine.engine.canvas;
   void set canvas(html.CanvasElement canvas) => _engine.engine.canvas = canvas;
 
   void toggleGrid() {
-    _engine.engine.toggleEdgeRendering();
+    _sim.renderEdges = !_sim.renderEdges;
   }
 }
diff --git a/lib/src/Engine.dart b/lib/src/Engine.dart
index 3653353..ad101ca 100644
--- a/lib/src/Engine.dart
+++ b/lib/src/Engine.dart
@@ -29,16 +29,6 @@ class Engine {
   // ms stuck in updateloop after which game will declare itself unresponsive
   final int SAFETY_TIMEOUT = 2000;
 
-  /// Grid Size
-  ///
-  /// Number of cells on x coordinate and y coordinate. Can be set individually.
-  Point get gridSize => Point<int>(_simulation.w, _simulation.h);
-  void set gridSize(Point<int> value) {
-    if (value.x <= 0 || value.y <= 0)
-      throw ArgumentError("grid size must not be smaller than 1");
-    _simulation = Simulation(value.x, value.y);
-  }
-
   num _updateLag = 0.0;
   num _drawLag = 0.0;
 
@@ -51,11 +41,8 @@ class Engine {
   Simulation _simulation;
   bool running = false;
 
-  Engine([x = 100, y = 100, this.canvas]) {
-    _simulation = Simulation(x, y);
-
+  Engine() {
     _elapsed.start();
-    _simulation.addRandomPattern(amount: 15, dispersal: 5);
     html.window.animationFrame.then(animFrame);
   }
 
@@ -64,16 +51,6 @@ class Engine {
     html.window.animationFrame.then(animFrame);
   }
 
-  void reset() {
-    _simulation.reset();
-    running = false;
-  }
-
-  void clear() {
-    _simulation = new Simulation(gridSize.x, gridSize.y);
-    running = false;
-  }
-
   void process(num now) {
     _drawLag += _elapsed.elapsedMilliseconds;
     _updateLag += _elapsed.elapsedMilliseconds;
@@ -101,6 +78,8 @@ class Engine {
   /// directly, since it is automatically taken care of by the processing function.
   /// If simulation should be advanced manually one time, prefer using step().
   void update() {
+    if (_simulation == null) return;
+
     Map<int, bool> simulationUpdate = _simulation.update();
     _simulation.mergeStateChanges(simulationUpdate);
 
@@ -123,16 +102,10 @@ class Engine {
   /// the internal engine processing. Does not do anything if no canvas is
   /// defined.
   void render([num interp]) {
-    if (canvas == null) return;
+    if (canvas == null || _simulation == null) return;
 
     _simulation.render(canvas, interp);
   }
 
-  void addPattern({int amount, int dispersal}) {
-    _simulation.addRandomPattern(amount: amount, dispersal: dispersal);
-  }
-
-  void toggleEdgeRendering() {
-    _simulation.renderEdges = !_simulation.renderEdges;
-  }
+  void set simulation(Simulation value) => _simulation = value;
 }
diff --git a/lib/src/Simulation.dart b/lib/src/Simulation.dart
index 42df2a4..fd8bbcb 100644
--- a/lib/src/Simulation.dart
+++ b/lib/src/Simulation.dart
@@ -1,5 +1,6 @@
 import 'dart:html' as html;
 import 'dart:math' as math;
+import 'dart:math';
 
 import 'package:rules_of_living/src/Grid.dart';
 import 'package:rules_of_living/src/rules/GameOfLife.dart';
@@ -8,7 +9,7 @@ import 'package:rules_of_living/src/rules/RuleSet.dart';
 enum CellPattern { SpaceShip, Blinker }
 
 class Simulation {
-  final Grid<bool> map;
+  Grid<bool> map;
   RuleSet rules = GameOfLife();
 
   bool _dirty = true;
@@ -20,6 +21,13 @@ class Simulation {
   int get w => map.width;
   int get h => map.height;
 
+  Point get gridSize => Point<int>(w, h);
+  void set gridSize(Point<int> value) {
+    if (value.x <= 0 || value.y <= 0)
+      throw ArgumentError("grid size must not be smaller than 1");
+    map = Grid(value.x, value.y);
+  }
+
   Simulation(int w, int h) : this.map = new Grid(w, h) {
     reset();
     print("Grid Created");
diff --git a/test/src/engine_test.dart b/test/src/engine_test.dart
index fcfefc2..bd184a4 100644
--- a/test/src/engine_test.dart
+++ b/test/src/engine_test.dart
@@ -31,12 +31,4 @@ void main() {
       expect(sut.canvas, isNotNull);
     });
   });
-  group("gridSize", () {
-    test("zero gridSizes throw ArgumentErrors", () {
-      expect(() => sut.gridSize = Point(0, 5), throwsArgumentError);
-    });
-    test("negative gridSizes throw ArgumentErrors", () {
-      expect(() => sut.gridSize = Point(1, -5), throwsArgumentError);
-    });
-  });
 }