/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
var CraftItem = Container.expand(function (itemType) {
	var self = Container.call(this);
	self.itemType = itemType;
	self.gridX = -1;
	self.gridY = -1;
	self.isDragging = false;
	self.startX = 0;
	self.startY = 0;
	// Create visual representation
	var itemGraphics = self.attachAsset(itemType, {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Add item type text
	var itemText = new Text2(getItemDisplayName(itemType), {
		size: 16,
		fill: 0xFFFFFF
	});
	itemText.anchor.set(0.5, 0.5);
	itemText.y = 50;
	self.addChild(itemText);
	self.down = function (x, y, obj) {
		self.startX = self.x;
		self.startY = self.y;
		self.startGridX = self.gridX;
		self.startGridY = self.gridY;
		if (self.gridX !== -1 && self.gridY !== -1) {
			// Remove from grid
			grid[self.gridY][self.gridX] = null;
		}
		self.isDragging = true;
		// Bring to front and add visual feedback
		self.parent.addChild(self);
		tween(self, {
			scaleX: 1.1,
			scaleY: 1.1,
			alpha: 0.8
		}, {
			duration: 200
		});
	};
	return self;
});
var GridCell = Container.expand(function (gridX, gridY) {
	var self = Container.call(this);
	self.gridX = gridX;
	self.gridY = gridY;
	var cellGraphics = self.attachAsset('grid_cell', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	cellGraphics.alpha = 0.3;
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x1a1a1a
});

/**** 
* Game Code
****/ 
// Sounds
// Grid cell
// Magical artifacts
// Advanced items
// Tools
// Basic materials
// Game constants
var GRID_WIDTH = 6;
var GRID_HEIGHT = 8;
var CELL_SIZE = 85;
var GRID_START_X = 2048 / 2 - GRID_WIDTH * CELL_SIZE / 2;
var GRID_START_Y = 600;
// Game state
var grid = [];
var items = [];
var draggedItem = null;
var score = 0;
// Crafting recipes
var recipes = {
	'wood': 'stick',
	'stick': 'axe',
	'stone': 'iron',
	'iron': 'pickaxe',
	'axe': 'sword',
	'pickaxe': 'shield',
	'sword': 'crystal',
	'shield': 'crystal',
	'crystal': 'enchanted_sword'
};
// Item values
var itemValues = {
	'wood': 1,
	'stone': 1,
	'stick': 3,
	'iron': 3,
	'axe': 10,
	'pickaxe': 10,
	'sword': 25,
	'shield': 25,
	'crystal': 50,
	'enchanted_sword': 100
};
// Initialize grid
for (var y = 0; y < GRID_HEIGHT; y++) {
	grid[y] = [];
	for (var x = 0; x < GRID_WIDTH; x++) {
		grid[y][x] = null;
		// Create visual grid cell
		var cell = new GridCell(x, y);
		cell.x = GRID_START_X + x * CELL_SIZE;
		cell.y = GRID_START_Y + y * CELL_SIZE;
		game.addChild(cell);
	}
}
// Score display
var scoreTxt = new Text2('Score: 0', {
	size: 60,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// Instructions
var instructionTxt = new Text2('Drag identical items together to combine them!', {
	size: 40,
	fill: 0xFFFF00
});
instructionTxt.anchor.set(0.5, 0);
instructionTxt.y = 100;
game.addChild(instructionTxt);
function getItemDisplayName(itemType) {
	var names = {
		'wood': 'Wood',
		'stone': 'Stone',
		'stick': 'Stick',
		'iron': 'Iron',
		'axe': 'Axe',
		'pickaxe': 'Pick',
		'sword': 'Sword',
		'shield': 'Shield',
		'crystal': 'Crystal',
		'enchanted_sword': 'Magic'
	};
	return names[itemType] || itemType;
}
function getGridPosition(x, y) {
	var gridX = Math.floor((x - GRID_START_X + CELL_SIZE / 2) / CELL_SIZE);
	var gridY = Math.floor((y - GRID_START_Y + CELL_SIZE / 2) / CELL_SIZE);
	if (gridX >= 0 && gridX < GRID_WIDTH && gridY >= 0 && gridY < GRID_HEIGHT) {
		return {
			x: gridX,
			y: gridY
		};
	}
	return null;
}
function isValidGridPosition(gridX, gridY) {
	return gridX >= 0 && gridX < GRID_WIDTH && gridY >= 0 && gridY < GRID_HEIGHT;
}
function placeItemInGrid(item, gridX, gridY) {
	if (!isValidGridPosition(gridX, gridY) || grid[gridY][gridX] !== null) {
		return false;
	}
	grid[gridY][gridX] = item;
	item.gridX = gridX;
	item.gridY = gridY;
	item.x = GRID_START_X + gridX * CELL_SIZE + CELL_SIZE / 2;
	item.y = GRID_START_Y + gridY * CELL_SIZE + CELL_SIZE / 2;
	return true;
}
function findEmptyGridSlot() {
	for (var y = 0; y < GRID_HEIGHT; y++) {
		for (var x = 0; x < GRID_WIDTH; x++) {
			if (grid[y][x] === null) {
				return {
					x: x,
					y: y
				};
			}
		}
	}
	return null;
}
function spawnRandomItem() {
	var itemTypes = ['wood', 'stone'];
	var randomType = itemTypes[Math.floor(Math.random() * itemTypes.length)];
	var emptySlot = findEmptyGridSlot();
	if (emptySlot) {
		var newItem = new CraftItem(randomType);
		game.addChild(newItem);
		items.push(newItem);
		placeItemInGrid(newItem, emptySlot.x, emptySlot.y);
		LK.getSound('place').play();
	}
}
function checkForCombinations(item) {
	if (item.gridX === -1 || item.gridY === -1) return false;
	var itemType = item.itemType;
	var gridX = item.gridX;
	var gridY = item.gridY;
	// Check adjacent cells for same item type
	var directions = [{
		dx: 0,
		dy: -1
	},
	// up
	{
		dx: 1,
		dy: 0
	},
	// right
	{
		dx: 0,
		dy: 1
	},
	// down
	{
		dx: -1,
		dy: 0
	} // left
	];
	for (var i = 0; i < directions.length; i++) {
		var dir = directions[i];
		var checkX = gridX + dir.dx;
		var checkY = gridY + dir.dy;
		if (isValidGridPosition(checkX, checkY) && grid[checkY][checkX]) {
			var otherItem = grid[checkY][checkX];
			if (otherItem.itemType === itemType && recipes[itemType]) {
				// Combine items
				var newItemType = recipes[itemType];
				// Remove both items
				grid[gridY][gridX] = null;
				grid[checkY][checkX] = null;
				// Remove from items array
				var itemIndex = items.indexOf(item);
				if (itemIndex !== -1) items.splice(itemIndex, 1);
				var otherIndex = items.indexOf(otherItem);
				if (otherIndex !== -1) items.splice(otherIndex, 1);
				// Destroy old items
				item.destroy();
				otherItem.destroy();
				// Create new item
				var newItem = new CraftItem(newItemType);
				game.addChild(newItem);
				items.push(newItem);
				placeItemInGrid(newItem, gridX, gridY);
				// Update score
				score += itemValues[newItemType] || 1;
				scoreTxt.setText('Score: ' + score);
				// Play sound
				LK.getSound('combine').play();
				// Flash effect
				LK.effects.flashObject(newItem, 0x00ff00, 500);
				return true;
			}
		}
	}
	return false;
}
// Spawn initial items
for (var i = 0; i < 4; i++) {
	spawnRandomItem();
}
// Game event handlers
var dragOffsetX = 0;
var dragOffsetY = 0;
game.move = function (x, y, obj) {
	if (draggedItem) {
		draggedItem.x = x - dragOffsetX;
		draggedItem.y = y - dragOffsetY;
	}
};
game.down = function (x, y, obj) {
	// Find if we clicked on an item
	for (var i = items.length - 1; i >= 0; i--) {
		var item = items[i];
		// Check if click is within item bounds (using center-anchored 60x60 items)
		var itemLeft = item.x - 35;
		var itemRight = item.x + 35;
		var itemTop = item.y - 35;
		var itemBottom = item.y + 35;
		if (x >= itemLeft && x <= itemRight && y >= itemTop && y <= itemBottom) {
			draggedItem = item;
			// Calculate offset for smooth dragging
			dragOffsetX = x - item.x;
			dragOffsetY = y - item.y;
			item.down(x, y, obj);
			break;
		}
	}
};
game.up = function (x, y, obj) {
	if (draggedItem) {
		// Reset visual feedback
		tween(draggedItem, {
			scaleX: 1,
			scaleY: 1,
			alpha: 1
		}, {
			duration: 200
		});
		var adjustedX = x - dragOffsetX;
		var adjustedY = y - dragOffsetY;
		var gridPos = getGridPosition(adjustedX, adjustedY);
		var placed = false;
		if (gridPos && grid[gridPos.y][gridPos.x] === null) {
			// Place in grid with smooth animation
			placed = placeItemInGrid(draggedItem, gridPos.x, gridPos.y);
			if (placed) {
				// Smooth placement animation
				tween(draggedItem, {
					x: GRID_START_X + gridPos.x * CELL_SIZE + CELL_SIZE / 2,
					y: GRID_START_Y + gridPos.y * CELL_SIZE + CELL_SIZE / 2
				}, {
					duration: 150
				});
				// Check for combinations
				checkForCombinations(draggedItem);
				LK.getSound('place').play();
			}
		} else if (gridPos && grid[gridPos.y][gridPos.x] !== null) {
			// Check if dropping on same item type for instant upgrade
			var targetItem = grid[gridPos.y][gridPos.x];
			if (targetItem.itemType === draggedItem.itemType && recipes[draggedItem.itemType]) {
				// Combine items instantly
				var newItemType = recipes[draggedItem.itemType];
				// Remove target item from grid
				grid[gridPos.y][gridPos.x] = null;
				// Remove both items from items array
				var draggedIndex = items.indexOf(draggedItem);
				if (draggedIndex !== -1) items.splice(draggedIndex, 1);
				var targetIndex = items.indexOf(targetItem);
				if (targetIndex !== -1) items.splice(targetIndex, 1);
				// Destroy old items
				draggedItem.destroy();
				targetItem.destroy();
				// Create new upgraded item
				var newItem = new CraftItem(newItemType);
				game.addChild(newItem);
				items.push(newItem);
				placeItemInGrid(newItem, gridPos.x, gridPos.y);
				// Update score
				score += itemValues[newItemType] || 1;
				scoreTxt.setText('Score: ' + score);
				// Play sound and visual effects
				LK.getSound('combine').play();
				LK.effects.flashObject(newItem, 0x00ff00, 500);
				placed = true;
			}
		}
		if (!placed) {
			// Return to original position or find empty slot
			if (draggedItem.startGridX !== -1 && draggedItem.startGridY !== -1 && grid[draggedItem.startGridY][draggedItem.startGridX] === null) {
				// Return to original grid position
				placeItemInGrid(draggedItem, draggedItem.startGridX, draggedItem.startGridY);
				tween(draggedItem, {
					x: draggedItem.startX,
					y: draggedItem.startY
				}, {
					duration: 300
				});
			} else {
				// Find new empty slot
				var emptySlot = findEmptyGridSlot();
				if (emptySlot) {
					placeItemInGrid(draggedItem, emptySlot.x, emptySlot.y);
					tween(draggedItem, {
						x: GRID_START_X + emptySlot.x * CELL_SIZE + CELL_SIZE / 2,
						y: GRID_START_Y + emptySlot.y * CELL_SIZE + CELL_SIZE / 2
					}, {
						duration: 300
					});
				} else {
					// Return to start position
					tween(draggedItem, {
						x: draggedItem.startX,
						y: draggedItem.startY
					}, {
						duration: 300
					});
				}
			}
		}
		draggedItem.isDragging = false;
		draggedItem = null;
		dragOffsetX = 0;
		dragOffsetY = 0;
	}
};
// Spawn timer
var spawnTimer = 0;
var spawnInterval = 120; // 2 seconds at 60fps
game.update = function () {
	spawnTimer++;
	if (spawnTimer >= spawnInterval) {
		spawnRandomItem();
		spawnTimer = 0;
		// Gradually increase spawn rate
		if (spawnInterval > 120) {
			spawnInterval--;
		}
	}
	// Check for game over (grid full)
	var gridFull = true;
	for (var y = 0; y < GRID_HEIGHT && gridFull; y++) {
		for (var x = 0; x < GRID_WIDTH && gridFull; x++) {
			if (grid[y][x] === null) {
				gridFull = false;
			}
		}
	}
	if (gridFull) {
		LK.showGameOver();
	}
	// Win condition - score threshold
	if (score >= 1000) {
		LK.showYouWin();
	}
};

===================================================================
--- original.js
+++ change.js
@@ -329,8 +329,37 @@
 				// Check for combinations
 				checkForCombinations(draggedItem);
 				LK.getSound('place').play();
 			}
+		} else if (gridPos && grid[gridPos.y][gridPos.x] !== null) {
+			// Check if dropping on same item type for instant upgrade
+			var targetItem = grid[gridPos.y][gridPos.x];
+			if (targetItem.itemType === draggedItem.itemType && recipes[draggedItem.itemType]) {
+				// Combine items instantly
+				var newItemType = recipes[draggedItem.itemType];
+				// Remove target item from grid
+				grid[gridPos.y][gridPos.x] = null;
+				// Remove both items from items array
+				var draggedIndex = items.indexOf(draggedItem);
+				if (draggedIndex !== -1) items.splice(draggedIndex, 1);
+				var targetIndex = items.indexOf(targetItem);
+				if (targetIndex !== -1) items.splice(targetIndex, 1);
+				// Destroy old items
+				draggedItem.destroy();
+				targetItem.destroy();
+				// Create new upgraded item
+				var newItem = new CraftItem(newItemType);
+				game.addChild(newItem);
+				items.push(newItem);
+				placeItemInGrid(newItem, gridPos.x, gridPos.y);
+				// Update score
+				score += itemValues[newItemType] || 1;
+				scoreTxt.setText('Score: ' + score);
+				// Play sound and visual effects
+				LK.getSound('combine').play();
+				LK.effects.flashObject(newItem, 0x00ff00, 500);
+				placed = true;
+			}
 		}
 		if (!placed) {
 			// Return to original position or find empty slot
 			if (draggedItem.startGridX !== -1 && draggedItem.startGridY !== -1 && grid[draggedItem.startGridY][draggedItem.startGridX] === null) {