/**** 
* Classes
****/ 
// DebugCell class
var DebugCell = Container.expand(function () {
	var self = Container.call(this);
	var cellGraphics = self.attachAsset('cell', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	cellGraphics.tint = Math.random() * 0xffffff;
	// Add a debug arrow to the debug cells
	var debugArrows = [];
	// Add a number label to the debug cells
	var numberLabel = new Text2('0', {
		size: 30,
		fill: 0xFFFFFF,
		weight: 800
	});
	numberLabel.anchor.set(.5, .5);
	self.addChild(numberLabel);
	self.update = function () {};
	self.down = function () {
		if (self.cell.type == 0 || self.cell.type == 1) {
			self.cell.type = self.cell.type == 1 ? 0 : 1;
			if (grid.pathFind()) {
				self.cell.type = self.cell.type == 1 ? 0 : 1;
				grid.pathFind();
				var notification = game.addChild(new Notification("Path is blocked!"));
				notification.x = 2048 / 2;
				notification.y = grid.height - 50;
			}
			grid.renderDebug();
		}
	};
	self.removeArrows = function () {
		while (debugArrows.length) {
			self.removeChild(debugArrows.pop());
		}
	};
	self.render = function (data) {
		switch (data.type) {
			case 0:
			case 2:
				{
					if (data.pathId != pathId) {
						self.removeArrows();
						numberLabel.setText("-");
						cellGraphics.tint = 0x880000;
						return;
					}
					numberLabel.visible = true;
					var tint = Math.floor(data.score / maxScore * 0x88);
					cellGraphics.tint = 0x88 - tint << 8 | tint;
					while (debugArrows.length > data.targets.length) {
						self.removeChild(debugArrows.pop());
					}
					for (var a = 0; a < data.targets.length; a++) {
						var destination = data.targets[a];
						var ox = destination.x - data.x;
						var oy = destination.y - data.y;
						var angle = Math.atan2(oy, ox);
						if (!debugArrows[a]) {
							debugArrows[a] = LK.getAsset('arrow', {
								anchorX: -.5,
								anchorY: 0.5
							});
							debugArrows[a].alpha = .5;
							self.addChildAt(debugArrows[a], 1);
							//							debugArrows = 
						}
						debugArrows[a].rotation = angle;
						//	debugArrow.rotation = angle;
					}
					break;
				}
			case 1:
				{
					self.removeArrows();
					cellGraphics.tint = 0xaaaaaa;
					numberLabel.visible = false;
					break;
				}
			case 3:
				{
					self.removeArrows();
					cellGraphics.tint = 0x008800;
					numberLabel.visible = false;
					break;
				}
		}
		numberLabel.setText(Math.floor(data.score / 1000) / 10);
	};
});
// Enemy class
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = Math.random() * .2 + .03;
	self.cellX = 0;
	self.cellY = 0;
	self.currentCellX = 0;
	self.currentCellY = 0;
	self.currentTarget = undefined;
	// Add health bar to the enemy
	var healthBarOutline = self.attachAsset('healthBarOutline', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	var healthBar = self.attachAsset('healthBar', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	healthBarOutline.y = healthBar.y = -enemyGraphics.height / 2 - 10; // Position the health bar above the enemy
	self.healthBar = healthBar;
});
//Class for the grid, handles all logic related to grid movement and interaction
var Grid = Container.expand(function (gridWidth, gridHeight) {
	var self = Container.call(this);
	self.cells = [];
	self.spawns = [];
	self.goals = [];
	for (var i = 0; i < gridWidth; i++) {
		self.cells[i] = [];
		for (var j = 0; j < gridHeight; j++) {
			self.cells[i][j] = {
				score: 0,
				pathId: 0
			};
		}
	}
	/*
				Cell Types
				0: Transparent floor
				1: Wall
				2: Spawn
				3: Goal
	*/
	for (var i = 0; i < gridWidth; i++) {
		for (var j = 0; j < gridHeight; j++) {
			// Set the type to 1 (wall) if the cell is on the edge of the grid, otherwise set it to 0 (ground)
			var cell = self.cells[i][j];
			var cellType = i === 0 || i === gridWidth - 1 || j <= 4 || j >= gridHeight - 4 ? 1 : 0;
			if (i > 11 - 3 && i <= 11 + 4) {
				if (j === 0) {
					cellType = 2;
					self.spawns.push(cell);
				} else if (j <= 4) {
					cellType = 0;
				} else if (j === gridHeight - 1) {
					cellType = 3;
					self.goals.push(cell);
				} else if (j >= gridHeight - 4) {
					cellType = 0;
				}
			}
			cell.type = cellType;
			cell.x = i;
			cell.y = j;
			/*if (cell.type == 0) {
				if (Math.random() > .5) {
					cell.type = 1;
				}
			}*/
			//Cache neighbours for speed
			cell.upLeft = self.cells[i - 1] && self.cells[i - 1][j - 1];
			cell.up = self.cells[i - 1] && self.cells[i - 1][j];
			cell.upRight = self.cells[i - 1] && self.cells[i - 1][j + 1];
			cell.left = self.cells[i][j - 1];
			cell.right = self.cells[i][j + 1];
			cell.downLeft = self.cells[i + 1] && self.cells[i + 1][j - 1];
			cell.down = self.cells[i + 1] && self.cells[i + 1][j];
			cell.downRight = self.cells[i + 1] && self.cells[i + 1][j + 1];
			cell.neighbors = [cell.upLeft, cell.up, cell.upRight, cell.right, cell.downRight, cell.down, cell.downLeft, cell.left];
			cell.targets = [];
			if (j > 3 && j <= gridHeight - 4) {
				var debugCell = new DebugCell();
				self.addChild(debugCell);
				debugCell.cell = cell;
				debugCell.x = i * CELL_SIZE;
				debugCell.y = j * CELL_SIZE;
				cell.debugCell = debugCell;
			}
		}
	}
	self.getCell = function (x, y) {
		return self.cells[x] && self.cells[x][y];
	};
	self.pathFind = function () {
		var before = new Date().getTime();
		var toProcess = self.goals.concat([]);
		maxScore = 0;
		pathId += 1;
		for (var a = 0; a < toProcess.length; a++) {
			toProcess[a].pathId = pathId;
		}
		function processNode(node, targetValue, targetNode) {
			if (node && node.type != 1) {
				if (node.pathId < pathId || targetValue < node.score) {
					node.targets = [targetNode];
				} else if (node.pathId == pathId && targetValue == node.score) {
					node.targets.push(targetNode);
				}
				if (node.pathId < pathId || targetValue < node.score) {
					node.score = targetValue;
					if (node.pathId != pathId) {
						toProcess.push(node);
					}
					node.pathId = pathId;
					if (targetValue > maxScore) {
						maxScore = targetValue;
					}
				}
			}
		}
		while (toProcess.length) {
			var nodes = toProcess;
			toProcess = [];
			for (var a = 0; a < nodes.length; a++) {
				var node = nodes[a];
				var targetScore = node.score + 14142;
				processNode(node.upLeft, targetScore, node);
				processNode(node.upRight, targetScore, node);
				processNode(node.downRight, targetScore, node);
				processNode(node.downLeft, targetScore, node);
				targetScore = node.score + 10000;
				processNode(node.up, targetScore, node);
				processNode(node.right, targetScore, node);
				processNode(node.down, targetScore, node);
				processNode(node.left, targetScore, node);
			}
		}
		for (var a = 0; a < self.spawns.length; a++) {
			if (self.spawns[a].pathId != pathId) {
				console.warn("Spawn blocked");
				return true;
			}
		}
		for (var a = 0; a < enemies.length; a++) {
			var enemy = enemies[a];
			var target = self.getCell(enemy.cellX, enemy.cellY);
			if (enemy.currentTarget) {
				if (enemy.currentTarget.pathId != pathId) {
					if (!target || target.pathId != pathId) {
						console.warn("Enemy blocked");
						return true;
					}
				}
			} else if (!target || target.pathId != pathId) {
				console.warn("Enemy blocked");
				return true;
			}
		}
		console.log("Speed", new Date().getTime() - before);
	};
	self.renderDebug = function () {
		for (var i = 0; i < gridWidth; i++) {
			for (var j = 0; j < gridHeight; j++) {
				var debugCell = self.cells[i][j].debugCell;
				if (debugCell) {
					debugCell.render(self.cells[i][j]);
				}
			}
		}
	};
	self.updateEnemy = function (enemy) {
		var cell = grid.getCell(enemy.cellX, enemy.cellY);
		if (cell.type == 3) {
			return true;
		}
		if (!enemy.currentTarget) {
			enemy.currentTarget = cell.targets[0];
		}
		if (enemy.currentTarget) {
			//Allows enemies to change direction right away.
			if (cell.score < enemy.currentTarget.score) {
				enemy.currentTarget = cell;
			}
			var ox = enemy.currentTarget.x - enemy.currentCellX;
			var oy = enemy.currentTarget.y - enemy.currentCellY;
			var dist = Math.sqrt(ox * ox + oy * oy);
			if (dist < enemy.speed) {
				enemy.cellX = Math.round(enemy.currentCellX);
				enemy.cellY = Math.round(enemy.currentCellY);
				enemy.currentTarget = undefined;
				return;
			}
			var angle = Math.atan2(oy, ox);
			enemy.currentCellX += Math.cos(angle) * enemy.speed;
			enemy.currentCellY += Math.sin(angle) * enemy.speed;
		}
		enemy.x = enemy.currentCellX * CELL_SIZE;
		enemy.y = enemy.currentCellY * CELL_SIZE;
	};
});
// Notification class
var Notification = Container.expand(function (message) {
	var self = Container.call(this);
	var notificationGraphics = self.attachAsset('notification', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	var notificationText = new Text2(message, {
		size: 50,
		fill: 0x000000,
		weight: 800
	});
	notificationText.anchor.set(0.5, 0.5);
	notificationGraphics.width = notificationText.width + 30;
	self.addChild(notificationText);
	self.alpha = 1;
	var fadeOutTime = 120; // 2 seconds at 60FPS
	self.update = function () {
		if (fadeOutTime > 0) {
			fadeOutTime--;
			self.alpha = Math.min(fadeOutTime / 120 * 2, 1);
		} else {
			self.destroy();
		}
	};
	return self;
});
// TowerPreview class for showing where towers can be placed
var TowerPreview = Container.expand(function () {
	var self = Container.call(this);
	// Create the preview square (2x2 grid cells)
	var previewGraphics = self.attachAsset('towerpreview', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Set the size to cover 2x2 grid cells
	previewGraphics.width = CELL_SIZE * 2;
	previewGraphics.height = CELL_SIZE * 2;
	// Initial state
	self.canPlace = false;
	self.gridX = 0;
	self.gridY = 0;
	// Update the preview color based on placement possibility
	self.updatePlacementStatus = function () {
		// If we can place, tint green, otherwise red
		previewGraphics.tint = self.canPlace ? 0x00FF00 : 0xFF0000;
	};
	// Check if the tower can be placed at the current position
	self.checkPlacement = function () {
		// Get the four cells that would be covered by this tower (2x2 grid)
		var canPlace = true;
		// First check if we're in the valid placement area (main square of the board)
		// Check if any part of the tower would be outside the main square
		if (self.gridY <= 4 || self.gridY + 1 >= grid.cells[0].length - 4) {
			canPlace = false;
		} else {
			// Check each of the 2x2 cells
			for (var i = 0; i < 2; i++) {
				for (var j = 0; j < 2; j++) {
					var cell = grid.getCell(self.gridX + i, self.gridY + j);
					// Can't place if any cell is undefined or not of type 0 (empty ground)
					if (!cell || cell.type !== 0) {
						canPlace = false;
						break;
					}
				}
				if (!canPlace) {
					break;
				}
			}
		}
		self.canPlace = canPlace;
		self.updatePlacementStatus();
	};
	// Snap the preview to the grid
	self.snapToGrid = function (x, y) {
		// Convert screen coordinates to grid coordinates
		// Offset by the grid's position
		var gridPosX = x - grid.x;
		var gridPosY = y - grid.y;
		// Convert to grid coordinates and round down to get the top-left cell
		self.gridX = Math.floor(gridPosX / CELL_SIZE);
		self.gridY = Math.floor(gridPosY / CELL_SIZE);
		// Position the preview at the intersection of the four cells
		// Adding CELL_SIZE to gridX and gridY gives us the center point
		self.x = grid.x + self.gridX * CELL_SIZE + CELL_SIZE / 2; // Center of the 2x2 grid
		self.y = grid.y + self.gridY * CELL_SIZE + CELL_SIZE / 2; // Center of the 2x2 grid
		// Check if we can place the tower here
		self.checkPlacement();
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x333333 //Init game with black background 
});

/**** 
* Game Code
****/ 
// Define cell size as a global constant
var CELL_SIZE = 76;
var pathId = 1;
var maxScore = 0;
var enemies = [];
var defenses = [];
var grid = new Grid(25, 29 + 6);
grid.x = 112;
grid.y = 112 - CELL_SIZE * 4;
grid.pathFind();
grid.renderDebug();
game.addChild(grid);
var offset = 0;
// Create tower preview
var towerPreview = new TowerPreview();
game.addChild(towerPreview);
towerPreview.visible = false;
// Handle drag events for tower placement
var isDragging = false;
game.down = function (x, y, obj) {
	towerPreview.visible = true;
	isDragging = true;
	towerPreview.snapToGrid(x, y);
};
game.move = function (x, y, obj) {
	if (isDragging) {
		towerPreview.snapToGrid(x, y);
	}
};
game.up = function (x, y, obj) {
	isDragging = false;
	// We're just previewing for now, so we don't place the tower yet
	// Later we'll add actual tower placement here
	towerPreview.visible = false;
};
game.update = function () {
	if (++offset % 100 == 0) {
		isFirst = false;
		var target = grid.spawns[Math.random() * grid.spawns.length >> 0];
		var enemy = grid.addChild(new Enemy());
		enemy.currentCellX = enemy.cellX = target.x;
		enemy.currentCellY = enemy.cellY = target.y;
		enemies.push(enemy);
	}
	for (var a = enemies.length - 1; a >= 0; a--) {
		if (grid.updateEnemy(enemies[a])) {
			grid.removeChild(enemies[a]);
			enemies.splice(a--, 1);
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -346,21 +346,27 @@
 	// Check if the tower can be placed at the current position
 	self.checkPlacement = function () {
 		// Get the four cells that would be covered by this tower (2x2 grid)
 		var canPlace = true;
-		// Check each of the 2x2 cells
-		for (var i = 0; i < 2; i++) {
-			for (var j = 0; j < 2; j++) {
-				var cell = grid.getCell(self.gridX + i, self.gridY + j);
-				// Can't place if any cell is undefined or not of type 0 (empty ground)
-				if (!cell || cell.type !== 0) {
-					canPlace = false;
+		// First check if we're in the valid placement area (main square of the board)
+		// Check if any part of the tower would be outside the main square
+		if (self.gridY <= 4 || self.gridY + 1 >= grid.cells[0].length - 4) {
+			canPlace = false;
+		} else {
+			// Check each of the 2x2 cells
+			for (var i = 0; i < 2; i++) {
+				for (var j = 0; j < 2; j++) {
+					var cell = grid.getCell(self.gridX + i, self.gridY + j);
+					// Can't place if any cell is undefined or not of type 0 (empty ground)
+					if (!cell || cell.type !== 0) {
+						canPlace = false;
+						break;
+					}
+				}
+				if (!canPlace) {
 					break;
 				}
 			}
-			if (!canPlace) {
-				break;
-			}
 		}
 		self.canPlace = canPlace;
 		self.updatePlacementStatus();
 	};
@@ -374,10 +380,10 @@
 		self.gridX = Math.floor(gridPosX / CELL_SIZE);
 		self.gridY = Math.floor(gridPosY / CELL_SIZE);
 		// Position the preview at the intersection of the four cells
 		// Adding CELL_SIZE to gridX and gridY gives us the center point
-		self.x = grid.x + self.gridX * CELL_SIZE + CELL_SIZE; // Center of the 2x2 grid
-		self.y = grid.y + self.gridY * CELL_SIZE + CELL_SIZE; // Center of the 2x2 grid
+		self.x = grid.x + self.gridX * CELL_SIZE + CELL_SIZE / 2; // Center of the 2x2 grid
+		self.y = grid.y + self.gridY * CELL_SIZE + CELL_SIZE / 2; // Center of the 2x2 grid
 		// Check if we can place the tower here
 		self.checkPlacement();
 	};
 	return self;
@@ -418,9 +424,9 @@
 	towerPreview.snapToGrid(x, y);
 };
 game.move = function (x, y, obj) {
 	if (isDragging) {
-		towerPreview.snapToGrid(x - CELL_SIZE / 2, y - CELL_SIZE / 2);
+		towerPreview.snapToGrid(x, y);
 	}
 };
 game.up = function (x, y, obj) {
 	isDragging = false;