diff --git a/packages/entity/index.js b/packages/entity/index.js
index fb69a4d..f63089e 100644
--- a/packages/entity/index.js
+++ b/packages/entity/index.js
@@ -94,12 +94,15 @@ export class Entity extends decorate(Resource) {
     this.once('destroyed', () => {
       this.removeAllTraits();
     });
-    this.initializeSynchronizedChildren();
+    // Bind to prevent lookup overhead.
+    this.tick = this.tick.bind(this);
+    // Fast props.
+    this.position = [0, 0];
+    this.visibleAabb = [0, 0, 0, 0];
+    // Fast path for instance.
     if ('undefined' !== typeof json) {
       this.fromJSON(json);
     }
-    // Bind to prevent lookup overhead.
-    this.tick = this.tick.bind(this);
   }
 
   acceptPacket(packet) {
diff --git a/packages/entity/list/index.js b/packages/entity/list/index.js
index 2807edb..a0f80d5 100644
--- a/packages/entity/list/index.js
+++ b/packages/entity/list/index.js
@@ -22,7 +22,6 @@ export class EntityList extends decorate(class {}) {
     this._entityTickers = []
     this._flatEntities = [];
     this._quadTree = new QuadTree();
-    this.initializeSynchronizedChildren();
   }
 
   *[Symbol.iterator]() {
@@ -76,7 +75,7 @@ export class EntityList extends decorate(class {}) {
       switch (step.op) {
         case 'add':
           // New entity. Create with patch as traits.
-          const newEntity = (new Entity()).fromJSON({
+          const newEntity = new Entity({
             traits: step.value,
           });
           newEntity.instanceUuid = uuid;
diff --git a/packages/entity/trait/index.js b/packages/entity/trait/index.js
index a9b3194..ab439b7 100644
--- a/packages/entity/trait/index.js
+++ b/packages/entity/trait/index.js
@@ -19,7 +19,6 @@ export class Trait extends decorate(class {}) {
     this._memoizedListeners = undefined;
     this.params = Object.assign({}, ctor.defaultParams(), params);
     this.state = I.fromJS(ctor.defaultState()).merge(I.fromJS(state));
-    this.initializeSynchronizedChildren();
     if (this.tick) {
       this.tick = this.tick.bind(this);
     }
diff --git a/packages/entity/traits/positioned.trait.js b/packages/entity/traits/positioned.trait.js
index 08ac0b7..e433deb 100644
--- a/packages/entity/traits/positioned.trait.js
+++ b/packages/entity/traits/positioned.trait.js
@@ -33,7 +33,8 @@ export class Positioned extends decorate(Trait) {
     const x = this.state.get('x') >> 2;
     const y = this.state.get('y') >> 2;
     this._position = [x, y];
-    this.entity.position = [x, y];
+    this.entity.position[0] = x;
+    this.entity.position[1] = y;
     if (AVOCADO_CLIENT) {
       this._relaxServerPositionConstraintIfNearerThan = 0;
       this.serverPosition = this._position;
@@ -50,7 +51,8 @@ export class Positioned extends decorate(Trait) {
   }
 
   on_positionChanged(oldPosition, newPosition) {
-    this.entity.position = newPosition;
+    this.entity.position[0] = newPosition[0];
+    this.entity.position[1] = newPosition[1];
     if (AVOCADO_SERVER) {
       const x = newPosition[0] << 2;
       const y = newPosition[1] << 2;
diff --git a/packages/graphics/traits/visible.trait.js b/packages/graphics/traits/visible.trait.js
index be0892e..e1e8bc8 100644
--- a/packages/graphics/traits/visible.trait.js
+++ b/packages/graphics/traits/visible.trait.js
@@ -57,7 +57,6 @@ export class Visible extends decorate(Trait) {
       this._container.isVisible = this.state.get('isVisible');
     }
     this._rawVisibleAabb = [0, 0, 0, 0];
-    this.entity.visibleAabb = [0, 0, 0, 0];
     this.scheduledBoundingBoxUpdate = true;
     this.trackPosition = this.params.trackPosition;
     const scale = this.state.get('visibleScale');
@@ -184,10 +183,14 @@ export class Visible extends decorate(Trait) {
   }
 
   translateVisibleAabb() {
-    this.entity.visibleAabb = Rectangle.translated(
+    const visibleAabb = Rectangle.translated(
       this._rawVisibleAabb,
       this.entity.position
     );
+    this.entity.visibleAabb[0] = visibleAabb[0];
+    this.entity.visibleAabb[1] = visibleAabb[1];
+    this.entity.visibleAabb[2] = visibleAabb[2];
+    this.entity.visibleAabb[3] = visibleAabb[3];
     this.entity.emit('visibleAabbChanged');
   }
 
diff --git a/packages/state/synchronized.js b/packages/state/synchronized.js
index 5cc6cb2..61fac57 100644
--- a/packages/state/synchronized.js
+++ b/packages/state/synchronized.js
@@ -14,12 +14,17 @@ export function Synchronized(Superclass) {
     constructor(...args) {
       super(...args);
       this.state = I.Map();
+      this._childrenNeedInitialization = true;
       this._childrenWithState = []
       this._childrenWithoutState = [];
       this._childrenTickers = [];
     }
 
-    initializeSynchronizedChildren() {
+    ensureChildrenAreSynchronized() {
+      if (!this._childrenNeedInitialization) {
+        return;
+      }
+      this._childrenNeedInitialization = false;
       const synchronizedChildren = this.synchronizedChildren();
       for (let i = 0; i < synchronizedChildren.length; ++i) {
         const key = synchronizedChildren[i];
@@ -84,6 +89,7 @@ export function Synchronized(Superclass) {
     }
 
     tickSynchronized(elapsed) {
+      this.ensureChildrenAreSynchronized();
       for (let i = 0; i < this._childrenTickers.length; ++i) {
         this._childrenTickers[i](elapsed);
       }
diff --git a/packages/topdown/layer.js b/packages/topdown/layer.js
index 649077f..9e96801 100644
--- a/packages/topdown/layer.js
+++ b/packages/topdown/layer.js
@@ -38,7 +38,6 @@ export class Layer extends decorate(class {}) {
     this.on('tilesetUriChanged', this.onTilesetUriChanged, this);
     this.onTilesetUriChanged();
     this.on('worldChanged', this.onWorldChanged, this);
-    this.initializeSynchronizedChildren();
   }
 
   addEntity(entity) {
diff --git a/packages/topdown/layers.js b/packages/topdown/layers.js
index d8c5675..c95ddd6 100644
--- a/packages/topdown/layers.js
+++ b/packages/topdown/layers.js
@@ -15,7 +15,6 @@ export class Layers extends decorate(class {}) {
   constructor() {
     super();
     this.layers = {};
-    this.initializeSynchronizedChildren();
   }
 
   *[Symbol.iterator]() {
diff --git a/packages/topdown/room.js b/packages/topdown/room.js
index c216405..dc8c53d 100644
--- a/packages/topdown/room.js
+++ b/packages/topdown/room.js
@@ -34,7 +34,6 @@ export class Room extends decorate(class {}) {
     this.layers.on('layerAdded', this.onLayerAdded, this);
     this.on('sizeChanged', this.onSizeChanged, this);
     this.on('worldChanged', this.onWorldChanged, this);
-    this.initializeSynchronizedChildren();
   }
 
   addEntityToLayer(entity, layerIndex = 0) {
diff --git a/packages/topdown/tiles.js b/packages/topdown/tiles.js
index e37468b..c64f362 100644
--- a/packages/topdown/tiles.js
+++ b/packages/topdown/tiles.js
@@ -17,7 +17,6 @@ export class Tiles extends decorate(class {}) {
   constructor() {
     super();
     this.data = I.List();
-    this.initializeSynchronizedChildren();
   }
 
   forEachTile(fn) {