/**** 
* Classes
****/ 
// Create an Exit class
var Exit = Container.expand(function () {
	var self = Container.call(this);
	var exitGraphics = self.attachAsset('Exit', {
		anchorX: 1,
		anchorY: 1,
		width: blockSize * 2,
		height: blockSize * 2
	});
});
// Create a Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5,
		width: blockSize,
		height: blockSize
	});
	self.speed = 5;
	self.update = function () {
		if (self.x < 0) {
			self.x = 0;
		}
		if (self.y < 0) {
			self.y = 0;
		}
		if (self.x > game.width) {
			self.x = game.width;
		}
		if (self.y > game.height) {
			self.y = game.height;
		}
		for (var i = 0; i < game.children.length; i++) {
			if (game.children[i] instanceof Wall && self.intersects(game.children[i])) {
				LK.showGameOver();
			}
		}
	};
});
//<Assets used in the game will automatically appear here>
// Create a Wall class
var Wall = Container.expand(function () {
	var self = Container.call(this);
	var wallGraphics = self.attachAsset('wall', {
		anchorX: 0.5,
		anchorY: 0.5
	});
});

/**** 
* Initialize Game
****/ 
// Function to generate a random maze
var game = new LK.Game({
	backgroundColor: 0x000000
});

/**** 
* Game Code
****/ 
// Function to generate a static maze
var blockSize = 50;
var background = LK.getAsset('Background1', {
	anchorX: 0.5,
	anchorY: 0.5
});
background.width = game.width;
background.height = game.height;
background.x = game.width / 2;
background.y = game.height / 2;
game.addChildAt(background, 0);
function generateMaze() {
	var mazeWidth = Math.floor(game.width / blockSize);
	var mazeHeight = Math.floor(game.height / blockSize);
	for (var i = 0; i < mazeWidth; i++) {
		for (var j = 0; j < mazeHeight; j++) {
			if (i === 0 || i === mazeWidth - 1 || j === 0 || j === mazeHeight - 1 || Math.random() < 0.2) {
				var wall = LK.getAsset('wall', {
					anchorX: 0.5,
					anchorY: 0.5
				});
				wall.width = blockSize;
				wall.height = blockSize;
				wall.x = i * blockSize + blockSize / 2;
				wall.y = j * blockSize + blockSize / 2;
				game.addChild(wall);
			}
		}
	}
}
generateMaze();
var player = game.addChild(new Player());
player.x = blockSize * 1.5;
player.y = game.height - blockSize * 1.5;
// Create an exit in the maze
var exit = game.addChild(new Exit());
exit.width = blockSize;
exit.height = blockSize;
exit.x = game.width - blockSize * 2.5;
exit.y = blockSize * 2.5;
// Add mouse down event to make player follow the cursor only when clicked and dragged
var dragNode = null;
game.down = function (x, y, obj) {
	dragNode = player;
};
game.move = function (x, y, obj) {
	if (dragNode) {
		var oldX = dragNode.x;
		var oldY = dragNode.y;
		dragNode.x = x - dragNode.width / 2;
		dragNode.y = y - dragNode.height / 2;
		for (var i = 0; i < game.children.length; i++) {
			if (game.children[i] instanceof Wall && dragNode.intersects(game.children[i])) {
				dragNode.x = oldX;
				dragNode.y = oldY;
				break;
			}
		}
		if (player.intersects(exit)) {
			LK.showGameOver();
		}
	}
};
game.up = function (x, y, obj) {
	dragNode = null;
};

===================================================================
--- original.js
+++ change.js
@@ -108,10 +108,19 @@
 	dragNode = player;
 };
 game.move = function (x, y, obj) {
 	if (dragNode) {
+		var oldX = dragNode.x;
+		var oldY = dragNode.y;
 		dragNode.x = x - dragNode.width / 2;
 		dragNode.y = y - dragNode.height / 2;
+		for (var i = 0; i < game.children.length; i++) {
+			if (game.children[i] instanceof Wall && dragNode.intersects(game.children[i])) {
+				dragNode.x = oldX;
+				dragNode.y = oldY;
+				break;
+			}
+		}
 		if (player.intersects(exit)) {
 			LK.showGameOver();
 		}
 	}