diff --git a/src/core/game-host.ts b/src/core/game-host.ts
index a3c1133..6a95614 100644
--- a/src/core/game-host.ts
+++ b/src/core/game-host.ts
@@ -11,11 +11,6 @@ import {createGameContext, IGameContext} from './game';
 
 export type GameHostStatus = 'created' | 'running' | 'disposed';
 
-export interface GameModule<TState extends Record<string, unknown>> {
-    registry: CommandRegistry<IGameContext<TState>>;
-    createInitialState: () => TState;
-}
-
 export class GameHost<TState extends Record<string, unknown>> {
     readonly context: IGameContext<TState>;
     readonly status: ReadonlySignal<GameHostStatus>;
@@ -152,11 +147,16 @@ export class GameHost<TState extends Record<string, unknown>> {
     }
 }
 
+export type GameModule<TState extends Record<string, unknown>> = {
+    registry: CommandRegistry<IGameContext<TState>>;
+    createInitialState: () => TState;
+}
+
 export function createGameHost<TState extends Record<string, unknown>>(
-    module: GameModule<TState>,
+  gameModule: GameModule<TState>
 ): GameHost<TState> {
     return new GameHost(
-        module.registry,
-        module.createInitialState,
+        gameModule.registry,
+        gameModule.createInitialState,
     );
 }
diff --git a/src/core/game.ts b/src/core/game.ts
index 207321c..1818fab 100644
--- a/src/core/game.ts
+++ b/src/core/game.ts
@@ -2,14 +2,11 @@ import {MutableSignal, mutableSignal} from "@/utils/mutable-signal";
 import {
     Command,
     CommandRegistry, CommandResult,
-    CommandRunnerContext, CommandRunnerContextExport,
+    CommandRunnerContextExport,
     CommandSchema,
     createCommandRegistry,
     createCommandRunnerContext,
-    parseCommandSchema,
-    registerCommand
 } from "@/utils/command";
-import type { GameModule } from './game-host';
 import {PromptValidator} from "@/utils/command/command-runner";
 
 export interface IGameContext<TState extends Record<string, unknown> = {} > {
@@ -66,28 +63,6 @@ export function createGameContext<TState extends Record<string, unknown> = {} >(
     return context;
 }
 
-/**
- * so that we can do `import * as tictactoe from './tic-tac-toe.ts';\n\n createGameContextFromModule(tictactoe);`
- * @param module
- */
-export function createGameContextFromModule<TState extends Record<string, unknown> = {} >(
-    module: {
-        registry: CommandRegistry<IGameContext<TState>>,
-        createInitialState: () => TState
-    },
-): IGameContext<TState> {
-    return createGameContext(module.registry, module.createInitialState);
-}
-
 export function createGameCommandRegistry<TState extends Record<string, unknown> = {} >() {
     return createCommandRegistry<IGameContext<TState>>();
-}
-
-export { GameHost, createGameHost } from './game-host';
-export type { GameHostStatus, GameModule } from './game-host';
-
-export function createGameModule<TState extends Record<string, unknown>>(
-    module: GameModule<TState>
-): GameModule<TState> {
-    return module;
 }
\ No newline at end of file
diff --git a/src/core/part-factory.ts b/src/core/part-factory.ts
index e78111e..0fbb77b 100644
--- a/src/core/part-factory.ts
+++ b/src/core/part-factory.ts
@@ -1,116 +1,6 @@
 import {Part} from "./part";
+import {Immutable} from "mutative";
 
-export type PartTemplate<TMeta = {}> = Omit<Partial<Part<TMeta>>, 'id'> & TMeta;
-
-export type PartPool<TMeta = {}> = {
-  parts: Record<string, Part<TMeta>>;
-  template: PartTemplate<TMeta>;
-  draw(): Part<TMeta> | undefined;
-  return(part: Part<TMeta>): void;
-  remaining(): number;
-};
-
-export function createPart<TMeta = {}>(
-  template: PartTemplate<TMeta>,
-  id: string
-): Part<TMeta> {
-  const part: Part<TMeta> = {
-    id,
-    regionId: template.regionId ?? '',
-    position: template.position ?? [],
-    ...template,
-  };
-  return part;
-}
-
-export function createParts<TMeta = {}>(
-  template: PartTemplate<TMeta>,
-  count: number,
-  idPrefix: string
-): Part<TMeta>[] {
-  const parts: Part<TMeta>[] = [];
-  for (let i = 0; i < count; i++) {
-    parts.push(createPart(template, `${idPrefix}-${i + 1}`));
-  }
-  return parts;
-}
-
-export function createPartPool<TMeta = {}>(
-  template: PartTemplate<TMeta>,
-  count: number,
-  idPrefix: string
-): PartPool<TMeta> {
-  const partsArray = createParts(template, count, idPrefix);
-  const parts: Record<string, Part<TMeta>> = {};
-  for (const part of partsArray) {
-    parts[part.id] = part;
-  }
-  const available = [...partsArray];
-
-  return {
-    parts,
-    template,
-    draw() {
-      return available.pop();
-    },
-    return(part: Part<TMeta>) {
-      part.regionId = '';
-      part.position = [];
-      available.push(part);
-    },
-    remaining() {
-      return available.length;
-    },
-  };
-}
-
-export function mergePartPools<TMeta = {}>(
-  ...pools: PartPool<TMeta>[]
-): PartPool<TMeta> {
-  if (pools.length === 0) {
-    return createEmptyPartPool<TMeta>();
-  }
-
-  const allPartsArray = pools.flatMap(p => Object.values(p.parts));
-  const allParts: Record<string, Part<TMeta>> = {};
-  for (const part of allPartsArray) {
-    allParts[part.id] = part;
-  }
-  const template = pools[0].template;
-  const available = allPartsArray.filter(p => p.regionId === '');
-
-  return {
-    parts: allParts,
-    template,
-    draw() {
-      return available.pop();
-    },
-    return(part: Part<TMeta>) {
-      part.regionId = '';
-      part.position = [];
-      available.push(part);
-    },
-    remaining() {
-      return available.length;
-    },
-  };
-}
-
-function createEmptyPartPool<TMeta>(): PartPool<TMeta> {
-  return {
-    parts: {},
-    template: {} as PartTemplate<TMeta>,
-    draw() {
-      return undefined;
-    },
-    return(_part: Part<TMeta>) {
-      // no-op for empty pool
-    },
-    remaining() {
-      return 0;
-    },
-  };
-}
 export function createPartsFromTable<T>(items: T[], getId: (item: T, index: number) => string, getCount?: ((item: T) => number) | number){
   const pool: Record<string, Part<T>> = {};
   for (const entry of items) {
@@ -121,9 +11,13 @@ export function createPartsFromTable<T>(items: T[], getId: (item: T, index: numb
         id,
         regionId: '',
         position: [],
-        ...entry
+        ...entry as Immutable<T>
       };
     }
   }
   return pool;
 }
+
+export function createParts<T>(item: T, getId: (index: number) => string, count?: number){
+  return createPartsFromTable([item], (_,index) => getId(index), count);
+}
\ No newline at end of file
diff --git a/src/core/part.ts b/src/core/part.ts
index 415b51c..33307b5 100644
--- a/src/core/part.ts
+++ b/src/core/part.ts
@@ -1,5 +1,5 @@
 import {RNG} from '@/utils/rng';
-import {Region} from '@/core/region';
+import {Immutable} from "mutative";
 
 export type Part<TMeta = {}> = {
   id: string;
@@ -11,7 +11,7 @@ export type Part<TMeta = {}> = {
   alignment?: string;
   regionId: string;
   position: number[];
-} & TMeta;
+} & Immutable<TMeta>;
 
 export function flip<TMeta>(part: Part<TMeta>) {
   if(!part.sides) return;
@@ -27,34 +27,3 @@ export function roll<TMeta>(part: Part<TMeta>, rng: RNG) {
   if(!part.sides) return;
   part.side = rng.nextInt(part.sides);
 }
-
-export function findPartById<TMeta>(parts: Record<string, Part<TMeta>>, id: string): Part<TMeta> | undefined {
-  return parts[id];
-}
-
-export function isCellOccupied<TMeta>(parts: Record<string, Part<TMeta>>, regionId: string, position: number[]): boolean {
-  const posKey = position.join(',');
-  return Object.values(parts).some(p => p.regionId === regionId && p.position.join(',') === posKey);
-}
-
-export function getPartAtPosition<TMeta>(parts: Record<string, Part<TMeta>>, regionId: string, position: number[]): Part<TMeta> | undefined {
-  const posKey = position.join(',');
-  return Object.values(parts).find(p => p.regionId === regionId && p.position.join(',') === posKey);
-}
-
-/**
- * O(1) cell occupancy check using Region.partMap
- */
-export function isCellOccupiedByRegion(region: Region, position: number[]): boolean {
-  return position.join(',') in region.partMap;
-}
-
-/**
- * O(1) part lookup using Region.partMap and parts Record
- */
-export function getPartAtPositionInRegion<TMeta>(region: Region, parts: Record<string, Part<TMeta>>, position: number[]): Part<TMeta> | undefined {
-  const posKey = position.join(',');
-  const partId = region.partMap[posKey];
-  if (!partId) return undefined;
-  return parts[partId];
-}
diff --git a/src/core/region.ts b/src/core/region.ts
index e7fbdd6..37dbee4 100644
--- a/src/core/region.ts
+++ b/src/core/region.ts
@@ -24,6 +24,15 @@ export function createRegion(id: string, axes: RegionAxis[]): Region {
   };
 }
 
+export function createRegionAxis(name: string, min?: number, max?: number, align?: 'start' | 'end' | 'center'): RegionAxis {
+  return {
+    name,
+    min,
+    max,
+    align,
+  };
+}
+
 function buildPartMap<TMeta>(region: Region, parts: Record<string, Part<TMeta>>) {
   const map: Record<string, string> = {};
   for (const childId of region.childIds) {
diff --git a/src/index.ts b/src/index.ts
index 0d88be0..2557fd6 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -5,19 +5,18 @@
 
 // Core types
 export type { IGameContext } from './core/game';
-export { createGameContext, createGameCommandRegistry } from './core/game';
+export { createGameCommandRegistry } from './core/game';
 
-export type { GameHost, GameHostStatus, GameModule } from './core/game';
-export { createGameHost, createGameModule } from './core/game';
+export type { GameHost, GameHostStatus, GameModule } from './core/game-host';
+export { createGameHost } from './core/game-host';
 
 export type { Part } from './core/part';
-export { flip, flipTo, roll, findPartById, isCellOccupied, getPartAtPosition, isCellOccupiedByRegion, getPartAtPositionInRegion } from './core/part';
+export { flip, flipTo, roll } from './core/part';
 
-export type { PartTemplate, PartPool } from './core/part-factory';
-export { createPart, createParts, createPartPool, mergePartPools, createPartsFromTable } from './core/part-factory';
+export { createParts, createPartsFromTable } from './core/part-factory';
 
 export type { Region, RegionAxis } from './core/region';
-export { createRegion, applyAlign, shuffle, moveToRegion } from './core/region';
+export { createRegion, createRegionAxis, applyAlign, shuffle, moveToRegion } from './core/region';
 
 // Utils
 export type { Command, CommandResult, CommandSchema, CommandParamSchema, CommandOptionSchema, CommandFlagSchema } from './utils/command';
@@ -27,7 +26,7 @@ export type { CommandRunner, CommandRunnerHandler, CommandRunnerContext, PromptE
 export { createCommandRegistry, registerCommand, unregisterCommand, hasCommand, getCommand, runCommand, runCommandParsed, createCommandRunnerContext, type CommandRegistry, type CommandRunnerContextExport } from './utils/command';
 
 export type { MutableSignal } from './utils/mutable-signal';
-export { mutableSignal, createEntityCollection } from './utils/mutable-signal';
+export { mutableSignal } from './utils/mutable-signal';
 
 export type { RNG } from './utils/rng';
 export { createRNG, Mulberry32RNG } from './utils/rng';
diff --git a/src/samples/tic-tac-toe.ts b/src/samples/tic-tac-toe.ts
index 28ac7f6..cff6288 100644
--- a/src/samples/tic-tac-toe.ts
+++ b/src/samples/tic-tac-toe.ts
@@ -1,5 +1,5 @@
 import {
-    createGameCommandRegistry, Part, createRegion, createPart, isCellOccupied as isCellOccupiedUtil,
+    createGameCommandRegistry, Part, createRegion,
     IGameContext
 } from '@/index';
 
@@ -18,7 +18,6 @@ const WINNING_LINES: number[][][] = [
 
 export type PlayerType = 'X' | 'O';
 export type WinnerType = PlayerType | 'draw' | null;
-
 type TicTacToePart = Part<{ player: PlayerType }>;
 
 export function createInitialState() {
@@ -91,7 +90,7 @@ function isValidMove(row: number, col: number): boolean {
 }
 
 export function isCellOccupied(host: TicTacToeGame, row: number, col: number): boolean {
-    return isCellOccupiedUtil(host.value.parts, 'board', [row, col]);
+    return !!host.value.board.partMap[`${row},${col}`];
 }
 
 export function hasWinningLine(positions: number[][]): boolean {
@@ -119,10 +118,10 @@ export function checkWinner(host: TicTacToeGame): WinnerType {
 export function placePiece(host: TicTacToeGame, row: number, col: number, player: PlayerType) {
     const board = host.value.board;
     const moveNumber = Object.keys(host.value.parts).length + 1;
-    const piece = createPart<{ player: PlayerType }>(
-        { regionId: 'board', position: [row, col], player },
-        `piece-${player}-${moveNumber}`
-    );
+    const piece: TicTacToePart = {
+        regionId: 'board', position: [row, col], player,
+        id: `piece-${player}-${moveNumber}`
+    }
     host.produce(state => {
         state.parts[piece.id] = piece;
         board.childIds.push(piece.id);
diff --git a/src/utils/mutable-signal.ts b/src/utils/mutable-signal.ts
index aaf33d2..aefe76c 100644
--- a/src/utils/mutable-signal.ts
+++ b/src/utils/mutable-signal.ts
@@ -1,4 +1,4 @@
-import {Signal, signal, SignalOptions} from '@preact/signals-core';
+import {Signal, SignalOptions} from '@preact/signals-core';
 import {create} from 'mutative';
 
 export class MutableSignal<T> extends Signal<T> {
@@ -40,35 +40,3 @@ export class MutableSignal<T> extends Signal<T> {
 export function mutableSignal<T>(initial?: T, options?: SignalOptions<T>): MutableSignal<T> {
   return new MutableSignal<T>(initial, options);
 }
-
-export type EntityCollection<T> = {
-  collection: Signal<Record<string, MutableSignal<T>>>;
-  remove(...ids: string[]): void;
-  add(...entities: (T & {id: string})[]): void;
-  get(id: string): MutableSignal<T>;
-}
-
-export function createEntityCollection<T>(): EntityCollection<T> {
-  const collection = signal({} as Record<string, MutableSignal<T>>);
-  const remove = (...ids: string[]) => {
-    collection.value = Object.fromEntries(
-        Object.entries(collection.value).filter(([id]) => !ids.includes(id)),
-    );
-  };
-
-  const add = (...entities: (T & {id: string})[]) => {
-    collection.value = {
-      ...collection.value,
-      ...Object.fromEntries(entities.map((e) => [e.id, mutableSignal(e)])),
-    };
-  };
-
-  const get = (id: string) => collection.value[id];
-
-  return {
-    collection,
-    remove,
-    add,
-    get
-  }
-}