diff --git a/src/app/app.component.ts b/src/app/app.component.ts
index 0c5a793..beded30 100644
--- a/src/app/app.component.ts
+++ b/src/app/app.component.ts
@@ -1,4 +1,6 @@
 import { Component } from '@angular/core';
+import { InnerNode, InnerNodeState } from './store/inner-node';
+import { Root } from './store/root';
 
 @Component({
   selector: 'app-root',
@@ -6,5 +8,26 @@ import { Component } from '@angular/core';
   styleUrls: ['./app.component.scss']
 })
 export class AppComponent {
-  title = 'frontend';
+  title = 'life';
+
+  /* tests
+  constructor() {
+
+    const root = new Root<InnerNode>();
+    root.log();
+
+    const l = new InnerNode();
+    const r = new InnerNode();
+    root.addChildren([l, r]);
+    root.log();
+
+    const rl = new InnerNode();
+    const rr = new InnerNode();
+    r.addChildren([rl, rr]);
+    root.log();
+
+    rr.changeKeys<InnerNodeState>({ dummy: 8 });
+    root.log();
+  }
+  */
 }
diff --git a/src/app/app.module.ts b/src/app/app.module.ts
index 4fdc9d0..a9173db 100644
--- a/src/app/app.module.ts
+++ b/src/app/app.module.ts
@@ -23,6 +23,8 @@ import { RemoveBlockComponent } from './components/modal/modals/remove-block/rem
 import { ToggleComponent } from './components/shared/toggle/toggle.component';
 import { TasksComponent } from './components/pages/page/tower/tasks/tasks.component';
 import { ColorPipe } from './pipes/color.pipe';
+import { Root } from './store/root';
+import { InnerNode, InnerNodeState } from './store/inner-node';
 
 @NgModule({
   declarations: [
diff --git a/src/app/components/pages/page/tower/block/block.component.ts b/src/app/components/pages/page/tower/block/block.component.ts
index b539ec1..80961fd 100644
--- a/src/app/components/pages/page/tower/block/block.component.ts
+++ b/src/app/components/pages/page/tower/block/block.component.ts
@@ -1,5 +1,5 @@
 import { Component, Input } from '@angular/core';
-import { Block } from '../../../../../model/block';
+import { Block, BlockState } from '../../../../../model/block';
 import { ModalService } from '../../../../../services/modal.service';
 import { ColoredBlock, Tower } from '../../../../../model/tower';
 
@@ -23,7 +23,7 @@ export class BlockComponent {
         isDone: this.block.isDone
       });
       console.log(description);
-      this.block.changeProperties({
+      this.block.changeKeys<BlockState>({
         tag: selected,
         description,
         isDone
diff --git a/src/app/components/pages/page/tower/tasks/tasks.component.ts b/src/app/components/pages/page/tower/tasks/tasks.component.ts
index 17eb6e8..1814f1b 100644
--- a/src/app/components/pages/page/tower/tasks/tasks.component.ts
+++ b/src/app/components/pages/page/tower/tasks/tasks.component.ts
@@ -1,5 +1,5 @@
 import { Component, ElementRef, Input, OnInit, ViewChild } from '@angular/core';
-import { Block } from '../../../../../model/block';
+import { Block, BlockState } from '../../../../../model/block';
 import { Tower } from '../../../../../model/tower';
 import { ModalService } from '../../../../../services/modal.service';
 import { CancelService } from '../../../../../services/cancel.service';
@@ -55,7 +55,7 @@ export class TasksComponent implements OnInit {
         change.created = new Date();
       }
 
-      block.changeProperties(change);
+      block.changeKeys<BlockState>(change);
     } catch {
       // pass
     }
diff --git a/src/app/model/block.ts b/src/app/model/block.ts
index 2d49058..eab92c4 100644
--- a/src/app/model/block.ts
+++ b/src/app/model/block.ts
@@ -1,30 +1,21 @@
 import { Serializable } from './serializable';
 import { IBlock } from '../interfaces/persistance/block';
 import { Node } from '../store/node';
+import { InnerNodeState } from '../store/inner-node';
 
-export class Block extends Serializable implements IBlock {
-  constructor(parent: Node, props: IBlock) {
-    super(parent, props, 'Block');
-    this.onAfterClone();
-  }
+export interface BlockState extends IBlock, InnerNodeState {}
 
-  protected onAfterClone(): void {
-    if (this.created.constructor.name !== 'Date') {
-      this.created = new Date(this.created);
-    }
-
-    // TODO: remove.
-    if (this.isDone === null || this.isDone === undefined) {
-      this.isDone = false;
-    }
-  }
-
-  changeProperties(values: Partial<IBlock>) {
-    this.changeKeys(values);
-  }
-
-  created: Date;
-  isDone: boolean;
+export class Block extends Serializable implements IBlock, BlockState {
+  readonly created: Date;
+  readonly isDone: boolean;
   readonly description: string;
   readonly tag: string;
+
+  constructor(props: IBlock) {
+    console.log('b');
+    if (props.created.constructor.name !== 'Date') {
+      props.created = new Date(props.created);
+    }
+    super(props, 'Block');
+  }
 }
diff --git a/src/app/model/page.ts b/src/app/model/page.ts
index ba12c64..b9493c9 100644
--- a/src/app/model/page.ts
+++ b/src/app/model/page.ts
@@ -1,17 +1,12 @@
 import { Serializable } from './serializable';
 import { IPage } from '../interfaces/persistance/page';
 import { Tower } from './tower';
-import { Node } from '../store/node';
+import { InnerNodeState } from '../store/inner-node';
 
-export class Page extends Serializable implements IPage {
-  constructor(parent: Node, props: IPage) {
-    super(parent, props, 'Page');
-  }
+export interface PageState extends InnerNodeState, IPage {}
 
+export class Page extends Serializable implements IPage, PageState {
   readonly name: string;
-  get towers(): Array<Tower> {
-    return this.children as Array<Tower>;
-  }
 
   readonly userData: {
     hideCreateTowerButton: boolean;
@@ -21,10 +16,17 @@ export class Page extends Serializable implements IPage {
     };
   };
 
+  constructor(props: IPage) {
+    super(props, 'Page');
+  }
+
+  get towers(): Array<Tower> {
+    return this.children as Array<Tower>;
+  }
+
   setHideCreateTowerButton(value: boolean) {
-    this.changeKey({
-      propertyName: 'userData',
-      value: {
+    this.changeKeys<PageState>({
+      userData: {
         ...this.userData,
         hideCreateTowerButton: value
       }
@@ -41,9 +43,8 @@ export class Page extends Serializable implements IPage {
     towers.splice(previousIndex, 1);
     towers.splice(currentIndex, 0, tower);
 
-    this.changeValue({
-      oldValue: this.towers,
-      newValue: towers
+    this.changeKeys<PageState>({
+      children: towers
     });
   }
 
@@ -53,17 +54,18 @@ export class Page extends Serializable implements IPage {
       hue = Math.random() * 360;
     } while (30 <= hue && hue <= 200);
 
-    new Tower(this, {
-      name,
-      blocks: [],
-      baseColor: { h: hue, s: 100, l: 50 }
-    });
+    this.addChildren([
+      new Tower({
+        name,
+        blocks: [],
+        baseColor: { h: hue, s: 100, l: 50 }
+      })
+    ]);
   }
 
   removeTower(tower: Tower) {
-    this.changeValue({
-      oldValue: this.towers,
-      newValue: this.towers.filter(t => t !== tower)
+    this.changeKeys<PageState>({
+      towers: this.towers.filter(t => t !== tower)
     });
   }
 }
diff --git a/src/app/model/serializable.ts b/src/app/model/serializable.ts
index 8eaae74..52c9834 100644
--- a/src/app/model/serializable.ts
+++ b/src/app/model/serializable.ts
@@ -1,10 +1,6 @@
-import { Cloneable } from '../store/cloneable';
-import { Node } from '../store/node';
+import { InnerNode } from '../store/inner-node';
 
-export class Serializable extends Cloneable {
-  protected type: string;
-
-  private static propertyList: any = {};
+export class Serializable extends InnerNode {
   static childrenMap: {
     [type: string]: {
       childrenConstructor: typeof Serializable;
@@ -13,12 +9,11 @@ export class Serializable extends Cloneable {
     };
   };
 
-  protected onAfterClone(): void {
-    // pass
-  }
+  private static propertyList: any = {};
+  protected type: string;
 
-  protected constructor(parent: Node, properties: any, type: string) {
-    super(parent);
+  protected constructor(properties: any, type: string) {
+    super();
 
     const compiledType = this.constructor.name;
     if (!Serializable.propertyList.hasOwnProperty(compiledType)) {
@@ -28,16 +23,15 @@ export class Serializable extends Cloneable {
       if (properties.hasOwnProperty(property)) {
         const propertyValue = properties[property];
         // This should be ran after the original constructor has finished.
-        console.log(type);
         if (property === Serializable.childrenMap[type].childrenListName) {
           new Promise(r => r()).then(() => {
-            for (let child of propertyValue) {
-              new Serializable.childrenMap[type].childrenConstructor(
-                this,
-                child,
-                Serializable.childrenMap[type].childrenType
-              );
-            }
+            const children = propertyValue.map(
+              c =>
+                new Serializable.childrenMap[type].childrenConstructor(c, Serializable.childrenMap[type].childrenType)
+            );
+            console.log(type, 'created');
+            this.addChildren(children);
+            console.log(type, 'added');
           });
         } else {
           this[property] = properties[property];
diff --git a/src/app/model/tower.ts b/src/app/model/tower.ts
index 7161212..fea3fac 100644
--- a/src/app/model/tower.ts
+++ b/src/app/model/tower.ts
@@ -3,16 +3,16 @@ import { lighten } from '../utils/color';
 import { Block } from './block';
 import { Serializable } from './serializable';
 import { hash } from '../utils/hash';
-import { Node } from '../store/node';
 import { IColor } from '../interfaces/color';
+import { InnerNodeState } from '../store/inner-node';
 
 export type ColoredBlock = Block & { color: IColor };
 
-export class Tower extends Serializable implements ITower {
-  protected type = 'Tower';
+export interface TowerState extends ITower, InnerNodeState {}
 
+export class Tower extends Serializable implements ITower, TowerState {
   tags: string[];
-  name: string;
+  readonly name: string;
 
   get blocks(): Array<Block> {
     return this.children as Array<Block>;
@@ -22,12 +22,11 @@ export class Tower extends Serializable implements ITower {
 
   readonly baseColor: IColor;
 
-  constructor(parent: Node, props: ITower) {
-    super(parent, props, 'Tower');
-    this.onAfterClone();
+  constructor(props: ITower) {
+    super(props, 'Tower');
   }
 
-  protected onAfterClone(): void {
+  protected onAfterClone() {
     this.blocks.sort((a, b) => {
       return a.created.getTime() - b.created.getTime();
     });
@@ -47,15 +46,15 @@ export class Tower extends Serializable implements ITower {
   }
 
   addBlock(props: { tag: string; description: string; isDone: boolean }) {
-    new Block(this, {
-      created: new Date(),
-      ...props
-    });
+    this.addChildren([
+      new Block({
+        created: new Date(),
+        ...props
+      })
+    ]);
   }
 
-  changeName(newName: string) {
-    // For optimization purposes.
-    this.name = newName;
-    this.mutatedUpdate();
+  changeName(name: string) {
+    this.changeKeys<TowerState>({ name });
   }
 }
diff --git a/src/app/services/data.service.ts b/src/app/services/data.service.ts
index 8c01ba4..555acc3 100644
--- a/src/app/services/data.service.ts
+++ b/src/app/services/data.service.ts
@@ -13,10 +13,6 @@ import { Observable } from 'rxjs/internal/Observable';
   providedIn: 'root'
 })
 export class DataService extends Root<Page> {
-  get pages(): Array<Page> {
-    return this.children;
-  }
-
   private readonly _safeChildren: BehaviorSubject<Array<Page>> = new BehaviorSubject(null);
   readonly safeChildren$: Observable<Array<Page>> = this._safeChildren.asObservable();
 
@@ -25,6 +21,30 @@ export class DataService extends Root<Page> {
     this.init().catch();
   }
 
+  get pages(): Array<Page> {
+    return this.children;
+  }
+
+  save(timeout: number) {
+    this.storeService.scheduleSave(this.pages, timeout);
+  }
+
+  addPage(name: string) {
+    const page = new Page({
+      name,
+      userData: {},
+      towers: []
+    });
+    this.addChildren([page]);
+    page.addTower();
+  }
+
+  removePage(page: Page) {
+    this.changeKeys<any>({
+      children: this.children.filter(c => c !== page)
+    });
+  }
+
   private async init() {
     const pages = await this.storeService.load();
     Serializable.childrenMap = {
@@ -44,43 +64,15 @@ export class DataService extends Root<Page> {
         childrenType: null
       }
     };
+    this.children$.subscribe(value => {
+      this.log();
+    });
 
-    for (let page of pages) {
-      new Page(this, page);
-    }
-    setTimeout(() => {
-      this.children$.subscribe(value => {
-        this.log();
-      });
-    }, 0);
+    this.addChildren(pages.map(p => new Page(p)));
 
     this.children$.subscribe(value => {
       this._safeChildren.next(value);
       this.save(0);
     });
   }
-
-  mutatedUpdate() {
-    this.save(2500);
-  }
-
-  save(timeout: number) {
-    this.storeService.scheduleSave(this.pages, timeout);
-  }
-
-  addPage(name: string) {
-    const page = new Page(this, {
-      name,
-      userData: {},
-      towers: []
-    });
-    page.addTower();
-  }
-
-  removePage(page: Page) {
-    this.changeValue({
-      oldValue: this.children,
-      newValue: this.children.filter(c => c !== page)
-    });
-  }
 }
diff --git a/src/app/services/store.service.ts b/src/app/services/store.service.ts
index a4b1596..819e04b 100644
--- a/src/app/services/store.service.ts
+++ b/src/app/services/store.service.ts
@@ -95,7 +95,7 @@ export class StoreService<T> {
 
   constructor() {
     const localStorageData = localStorage.getItem(LOCAL_STORAGE_KEY);
-    this.storedData = JSON.parse(localStorageData ? localStorageData : this.mockData) as T;
+    this.storedData = JSON.parse(false ? localStorageData : this.mockData) as T;
   }
 
   scheduleSave(data: T, timeout: number) {
diff --git a/src/app/store/cloneable.ts b/src/app/store/cloneable.ts
deleted file mode 100644
index 317e279..0000000
--- a/src/app/store/cloneable.ts
+++ /dev/null
@@ -1,102 +0,0 @@
-import { InnerNode } from './inner-node';
-import { Node } from './node';
-
-export abstract class Cloneable extends InnerNode {
-  protected constructor(parent: Node) {
-    super(parent);
-  }
-
-  protected abstract onAfterClone(): void;
-
-  protected cloneWithMap(map: (node: this) => void): this {
-    const insides = Object.getOwnPropertyDescriptors(this);
-
-    const insidesProxy = new Proxy(insides, {
-      get: (target, prop, proxy) => {
-        if (prop == '__target__') {
-          return target;
-        }
-        if (target.hasOwnProperty(prop)) {
-          const value = target[prop as string].value;
-          if (typeof value === 'function') {
-            return value.bind(proxy);
-          }
-          return value;
-        } else if (target.prototype.hasOwnProperty(prop)) {
-          const value = target.prototype[prop];
-          if (typeof value === 'function') {
-            return value.bind(proxy);
-          }
-          return value;
-        }
-      },
-      set: (target, prop, value) => {
-        return (target[prop as string].value = value);
-      }
-    });
-    map(<any>insidesProxy);
-
-    return this.cloneFromInsides(<any>insidesProxy.__target__);
-  }
-
-  protected cloneWithAdd({ propertyName, value }: { value: any; propertyName: string }): this {
-    if (this[propertyName] === value) {
-      return this;
-    }
-
-    const insides = Object.getOwnPropertyDescriptors(this);
-    insides[propertyName].value = value;
-    return this.cloneFromInsides(insides);
-  }
-
-  protected cloneWithChangedKeys(props: { [propertyName: string]: any }): this {
-    const insides = Object.getOwnPropertyDescriptors(this);
-
-    for (let key in props) {
-      if (props.hasOwnProperty(key)) {
-        if (insides.hasOwnProperty(key)) {
-          insides[key].value = props[key];
-        } else {
-          // @ts-ignore
-          insides[key] = {
-            value: props[key]
-          };
-        }
-      }
-    }
-
-    return this.cloneFromInsides(insides);
-  }
-
-  protected cloneWithModify({ oldValue, newValue }: { oldValue: any; newValue: any }): this {
-    if (oldValue === newValue) {
-      return this;
-    }
-
-    const insides = Object.getOwnPropertyDescriptors(this);
-
-    let wasMatch = false;
-    for (let name in insides) {
-      if (insides.hasOwnProperty(name) && insides[name].value === oldValue) {
-        insides[name].value = newValue;
-        wasMatch = true;
-      }
-    }
-
-    if (!wasMatch) {
-      throw new TypeError(`Object has no property with value: ${oldValue.toString()}`);
-    }
-
-    return this.cloneFromInsides(insides);
-  }
-
-  private cloneFromInsides(insides): this {
-    insides.id.value = Node.id++;
-    insides.copyCount.value++;
-    Node.sumCopyCount++;
-
-    const clone = Object.create(Object.getPrototypeOf(this), insides);
-    clone.onAfterClone();
-    return clone;
-  }
-}
diff --git a/src/app/store/inner-node.ts b/src/app/store/inner-node.ts
index 6f37af8..66409ba 100644
--- a/src/app/store/inner-node.ts
+++ b/src/app/store/inner-node.ts
@@ -1,9 +1,18 @@
-import { Node } from './node';
+import { Node, NodeState } from './node';
 
-export abstract class InnerNode extends Node {
-  readonly children: Array<InnerNode> = [];
-  protected parent: Node;
+export interface InnerNodeState extends NodeState {
+  dummy: any;
+}
+
+export class InnerNode extends Node implements InnerNodeState {
+  readonly dummy = 3;
+  parent: Node;
   private nextVersion: this = null;
+  readonly children: Array<InnerNode> = [];
+
+  constructor() {
+    super();
+  }
 
   get latestVersion(): this {
     let version;
@@ -13,40 +22,34 @@ export abstract class InnerNode extends Node {
     return version;
   }
 
-  mutatedUpdate() {
-    this.parent.mutatedUpdate();
+  addChildren(children: Array<InnerNode>) {
+    super.addChildren.call(this.latestVersion, children);
   }
 
-  map(map: (a: this) => void) {
-    return this.update((self: this) => this.cloneWithMap.call(self, map));
-  }
-
-  changeKeys(props: { [propertyName: string]: any }): this {
-    return this.update((self: this) => this.cloneWithChangedKeys.call(self, props));
-  }
-
-  addChild(update: { child: InnerNode }) {
-    super.addChild.call(this.latestVersion, update);
-  }
-
-  changeChild(update: { oldValue: InnerNode; newValue: InnerNode }) {
+  replaceChild(update: { oldValue: InnerNode; newValue: InnerNode }) {
     super.replaceChild.call(this.latestVersion, update);
   }
 
-  protected abstract cloneWithMap(map: (a: this) => void): this;
-  protected abstract cloneWithChangedKeys(props: { [propertyName: string]: any }): this;
-
-  private update(cloneMethod: (self: this) => this): this {
+  changeKeys<T extends NodeState>(props: Partial<T>): this {
     if (this.nextVersion !== null) {
-      this.latestVersion.update(cloneMethod);
+      this.latestVersion.changeKeys(props);
     }
 
-    const clone = cloneMethod(this);
-    if (clone === this) {
-      return this;
+    const clone = this.cloneWithChangedKeys(props);
+
+    let shouldClone = false;
+    for (const prop in props) {
+      // @ts-ignore
+      if (props.hasOwnProperty(prop) && props[prop] !== this[prop]) {
+        shouldClone = true;
+        break;
+      }
+    }
+    if (!shouldClone) {
+      return;
     }
 
-    for (let child of clone.children) {
+    for (const child of clone.children) {
       child.parent = clone;
     }
 
@@ -58,4 +61,28 @@ export abstract class InnerNode extends Node {
     this.nextVersion = clone;
     return clone;
   }
+
+  protected onAfterClone() {}
+
+  protected cloneWithChangedKeys<T extends NodeState>(props: Partial<T>): this {
+    const insides = Object.getOwnPropertyDescriptors(this);
+
+    for (const key in props) {
+      if (props.hasOwnProperty(key)) {
+        if (insides.hasOwnProperty(key)) {
+          insides[key].value = props[key];
+        } else {
+          // @ts-ignore
+          insides[key] = {
+            value: props[key]
+          };
+        }
+      }
+    }
+
+    const clone = Object.create(Object.getPrototypeOf(this), insides);
+    clone.initiate();
+    clone.onAfterClone();
+    return clone;
+  }
 }
diff --git a/src/app/store/node.ts b/src/app/store/node.ts
index 1bee7cd..fc6363f 100644
--- a/src/app/store/node.ts
+++ b/src/app/store/node.ts
@@ -1,22 +1,24 @@
-import { InnerNode } from './inner-node';
 import { Unique } from './unique';
+import { InnerNode } from './inner-node';
 
-export abstract class Node extends Unique {
-  readonly children: Array<InnerNode>;
-  // TODO: fix types.
-  protected abstract changeKeys(props: any): this;
-  abstract mutatedUpdate(): void;
+export interface NodeState {
+  children: Array<InnerNode>;
+}
 
-  private copyCount = 0;
+export abstract class Node extends Unique implements NodeState {
+  protected copyCount = 1;
+  abstract readonly children: Array<InnerNode>;
+
+  protected abstract changeKeys<T extends NodeState>(props: Partial<T>): this;
 
   protected initiate() {
     super.initiate();
-    this.copyCount++;
+    ++this.copyCount;
   }
 
-  addChild({ child }: { child: InnerNode }) {
-    this.changeKeys({
-      children: [...this.children, child]
+  addChildren(children: Array<InnerNode>) {
+    this.changeKeys<NodeState>({
+      children: [...this.children, ...children]
     });
   }
 
@@ -25,7 +27,7 @@ export abstract class Node extends Unique {
       return;
     }
 
-    this.changeKeys({
+    this.changeKeys<NodeState>({
       children: this.children.map(c => (c === oldValue ? newValue : c))
     });
   }
@@ -33,7 +35,7 @@ export abstract class Node extends Unique {
   protected _log(indent = ''): string {
     const basicInfo = `${indent} - ${this.constructor.name}, #${this.id}`;
     let response = `${basicInfo}${' '.repeat(25 - basicInfo.length)}siblings: ${this.copyCount}\n`;
-    for (let c of this.children) {
+    for (const c of this.children) {
       response += `${c._log(indent + '  ')}`;
     }
     return response;
diff --git a/src/app/store/root.ts b/src/app/store/root.ts
index 54c62e8..7483da1 100644
--- a/src/app/store/root.ts
+++ b/src/app/store/root.ts
@@ -1,12 +1,16 @@
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
 import { Observable } from 'rxjs/internal/Observable';
-import { Node } from './node';
+import { Node, NodeState } from './node';
 import { InnerNode } from './inner-node';
 
 export class Root<T extends InnerNode> extends Node {
   private readonly _children: BehaviorSubject<Array<T>> = new BehaviorSubject([]);
   readonly children$: Observable<Array<T>> = this._children.asObservable();
 
+  constructor() {
+    super();
+  }
+
   get children(): Array<T> {
     return this._children.getValue();
   }
@@ -15,27 +19,14 @@ export class Root<T extends InnerNode> extends Node {
     this._children.next(value);
   }
 
-  mutatedUpdate() {
-    // pass
-  }
-
-  changeValue({ oldValue, newValue }: { oldValue: any; newValue: any }) {
-    if (this.children !== oldValue) {
-      throw new TypeError('Only children can be changed.');
-    }
-    this.children = newValue;
-    for (let child of this.children) {
-      child.parent = this;
-    }
-  }
-
-  changeKey({ propertyName, value }: { propertyName: string; value: any }) {
-    if (propertyName !== 'children') {
-      throw new TypeError('Only children can be changed.');
-    }
-    this.children = value;
-    for (let child of this.children) {
-      child.parent = this;
+  changeKeys<U extends NodeState>(props: Partial<U>): this {
+    if (props.hasOwnProperty('children')) {
+      // @ts-ignore
+      this.children = props.children;
+      for (const child of this.children) {
+        child.parent = this;
+      }
     }
+    return this;
   }
 }
diff --git a/src/app/store/unique.ts b/src/app/store/unique.ts
index a8228e4..a0500c1 100644
--- a/src/app/store/unique.ts
+++ b/src/app/store/unique.ts
@@ -6,10 +6,10 @@ export abstract class Unique extends Initiable {
     return Unique.nextId;
   }
 
+  private _id: number;
   get id(): number {
     return this._id;
   }
-  private _id: number;
 
   protected initiate() {
     this._id = Unique.nextId++;