/**** 
* Classes
****/
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdGraphics = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.velocityY = 0;
	self.gravity = 0.6;
	self.flapPower = -15;
	self.flap = function () {
		self.velocityY = self.flapPower;
	};
	self.updatePhysics = function () {
		self.velocityY += self.gravity;
		self.y += self.velocityY;
		// Lock the bird's horizontal position to the center of the screen
		self.x = game.width / 4;
		// Keep the bird within the game boundaries and check for ground collision
		if (self.y > game.height - ground.height) {
			self.y = game.height - ground.height;
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
		} else if (self.y < 0) {
			self.y = 0;
		}
	};
});
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var topPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0.5,
		flipY: 1
	});
	var bottomPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	var gapSize = 200;
	self.setGap = function (gapY) {
		topPipe.y = gapY - gapSize / 2 - topPipe.height / 2;
		bottomPipe.y = gapY + gapSize / 2 + bottomPipe.height / 2;
	};
	self.move = function () {
		self.x -= 4; // Increase the speed of the pipes to move left
	};
	self.resetPosition = function (newX) {
		self.x = newX;
	};
	self.getTopPipe = function () {
		return topPipe;
	};
	self.getBottomPipe = function () {
		return bottomPipe;
	};
});

/**** 
* Initialize Game
****/
var game = new LK.Game({
	backgroundColor: 0x87CEEB // Sky blue background
});

/**** 
* Game Code
****/
// Initialize background asset
var background = game.addChild(LK.getAsset('background', {
	anchorX: 0.5,
	anchorY: 0.5
}));
background.y = game.height / 2;
// Initialize ground asset
var ground = game.addChild(LK.getAsset('ground', {
	anchorX: 0.0,
	anchorY: 1.0,
	x: 0,
	y: game.height
}));
var bird;
function startGame() {
	// Clear the main menu
	if (mainMenu) {
		mainMenu.destroy();
		mainMenu = null;
	}
	// Create and initialize the bird
	var bird = game.addChild(new Bird());
	bird.x = game.width / 4;
	bird.y = game.height / 2;
	var obstacles = [];
	// Create and position pipes according to the generated positions
	// Add touch event to make the bird flap and jump
	game.on('down', function (obj) {
		// Ensure bird is defined and accessible
		if (bird) {
			bird.flap();
		}
	});
	// Set up the game tick event for the level
	var pipeCreationInterval = 1500; // Time in milliseconds between pipe creation
	var lastPipeCreationTime = Date.now();
	LK.on('tick', function () {
		// Update bird physics
		bird.updatePhysics();
		// Move background
		background.x -= 2;
		if (background.x <= -background.width / 2) {
			background.x = background.width / 2;
		}
		// Move ground
		ground.x -= 2;
		if (ground.x <= -ground.width) {
			ground.x = 0;
		}
		// Move obstacles and create new ones at intervals
		if (obstacles) {
			for (var i = obstacles.length - 1; i >= 0; i--) {
				obstacles[i].move();
				// Remove off-screen obstacles
				if (obstacles[i].x < -obstacles[i].width) {
					obstacles[i].destroy();
					obstacles.splice(i, 1);
				}
			}
			// Check if it's time to create a new pipe
			if (Date.now() - lastPipeCreationTime > pipeCreationInterval) {
				var obstacle = game.addChild(new Obstacle());
				obstacle.setGap(Math.random() * (game.height - 200) + 100);
				obstacle.x = game.width;
				obstacles.push(obstacle);
				lastPipeCreationTime = Date.now();
			}
		}
		// Check for collision between the bird and the pipes and increment score
		var passedPipe = false;
		for (var i = 0; i < obstacles.length; i++) {
			var obstacle = obstacles[i];
			var topPipe = obstacle.getTopPipe();
			var bottomPipe = obstacle.getBottomPipe();
			if (bird.intersects(topPipe) || bird.intersects(bottomPipe)) {
				LK.effects.flashScreen(0xff0000, 1000);
				LK.showGameOver();
				break;
			} else if (bird.x > topPipe.x + topPipe.width && !obstacle.passed) {
				obstacle.passed = true;
				passedPipe = true;
			}
		}
		if (passedPipe) {
			LK.setScore(LK.getScore() + 1);
			scoreTxt.setText(LK.getScore());
		}
	});
}
/**** 
* Main Menu Code
****/
var menuBackground = LK.getAsset('ground', {
	width: game.width,
	height: game.height,
	color: 0x87CEEB
});
function showMainMenu() {
	// Remove existing game elements
	if (bird) {
		bird.destroy();
		bird = null;
	}
	if (obstacles) {
		for (var i = obstacles.length - 1; i >= 0; i--) {
			obstacles[i].destroy();
			obstacles.splice(i, 1);
		}
	}
	game.addChild(menuBackground);
	// Create and show the main menu
	mainMenu = game.addChild(new MainMenu());
}
/**** 
* Event Listeners
****/
// Listen for the game over event and show the main menu when triggered
LK.on('gameOver', function () {
	showMainMenu();
});
// Listen for the level completed event and show the main menu when triggered
LK.on('levelCompleted', function () {
	showMainMenu();
});
// Initial display of the main menu
showMainMenu();

===================================================================
--- original.js
+++ change.js
@@ -80,8 +80,9 @@
 	anchorY: 1.0,
 	x: 0,
 	y: game.height
 }));
+var bird;
 function startGame() {
 	// Clear the main menu
 	if (mainMenu) {
 		mainMenu.destroy();