/**** 
* Classes
****/ 
// Block class for a single voxel block
var Block = Container.expand(function () {
	var self = Container.call(this);
	// Default block type is 'dirt'
	self.type = 'dirt';
	// Attach the block asset, anchor at center
	self.blockAsset = self.attachAsset('block_' + self.type, {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Supported types: 'dirt', 'grass', 'stone'
	// Set block type and update asset
	self.setType = function (type) {
		self.type = type;
		// Remove old asset if present
		if (self.blockAsset) {
			self.removeChild(self.blockAsset);
		}
		self.blockAsset = self.attachAsset('block_' + self.type, {
			anchorX: 0.5,
			anchorY: 0.5
		});
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x000000
});

/**** 
* Game Code
****/ 
;
// --- Block Placement/Removal Controls ---
// Helper: Convert screen/game coordinates to grid coordinates
function getGridCoords(x, y) {
	var gx = Math.floor((x - gridOffsetX) / BLOCK_SIZE);
	var gy = Math.floor((y - gridOffsetY) / BLOCK_SIZE);
	if (gx < 0 || gx >= GRID_WIDTH || gy < 0 || gy >= GRID_HEIGHT) return null;
	return {
		x: gx,
		y: gy
	};
}
// Track current action: 'place' or 'remove'
var currentAction = 'place'; // Default to placing blocks
// Track current block type for placement
var blockTypes = ['dirt', 'grass', 'stone'];
var currentBlockTypeIndex = 0;
var currentBlockType = blockTypes[currentBlockTypeIndex];
// Palette UI: tap top-right to toggle between 'place' and 'remove', and select block type
var paletteSize = 180;
var paletteX = 2048 - paletteSize - 40;
var paletteY = 40;
// Draw palette action button (place/remove)
var paletteBtn = LK.getAsset('block_dirt', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: paletteX + paletteSize / 2,
	y: paletteY + paletteSize / 2,
	width: paletteSize,
	height: paletteSize
});
game.addChild(paletteBtn);
// Draw block swap button (cycle block type)
var swapBtnSize = 120;
var swapBtnX = paletteX + paletteSize / 2;
var swapBtnY = paletteY + paletteSize + 40 + swapBtnSize / 2;
var swapBtn = LK.getAsset('block_' + currentBlockType, {
	anchorX: 0.5,
	anchorY: 0.5,
	x: swapBtnX,
	y: swapBtnY,
	width: swapBtnSize,
	height: swapBtnSize
});
game.addChild(swapBtn);
// Overlay text for mode
var paletteTxt = new Text2('Place', {
	size: 60,
	fill: "#fff"
});
paletteTxt.anchor.set(0.5, 0.5);
paletteTxt.x = paletteBtn.x;
paletteTxt.y = paletteBtn.y;
game.addChild(paletteTxt);
// Overlay text for block type
var swapTxt = new Text2(currentBlockType.charAt(0).toUpperCase() + currentBlockType.slice(1), {
	size: 40,
	fill: "#fff"
});
swapTxt.anchor.set(0.5, 0.5);
swapTxt.x = swapBtn.x;
swapTxt.y = swapBtn.y;
game.addChild(swapTxt);
// Toggle action on palette tap
paletteBtn.down = function (x, y, obj) {
	currentAction = currentAction === 'place' ? 'remove' : 'place';
	paletteTxt.setText(currentAction.charAt(0).toUpperCase() + currentAction.slice(1));
};
// Cycle block type on swapBtn tap
swapBtn.down = function (x, y, obj) {
	currentBlockTypeIndex = (currentBlockTypeIndex + 1) % blockTypes.length;
	currentBlockType = blockTypes[currentBlockTypeIndex];
	// Update swapBtn asset
	swapBtn.setAsset('block_' + currentBlockType, {
		anchorX: 0.5,
		anchorY: 0.5,
		x: swapBtnX,
		y: swapBtnY,
		width: swapBtnSize,
		height: swapBtnSize
	});
	swapTxt.setText(currentBlockType.charAt(0).toUpperCase() + currentBlockType.slice(1));
};
// Handle placing/removing blocks on grid
game.down = function (x, y, obj) {
	// Ignore palette area
	if (x >= paletteX && x <= paletteX + paletteSize && y >= paletteY && y <= paletteY + paletteSize) {
		// Let paletteBtn handle its own .down
		return;
	}
	var grid = getGridCoords(x, y);
	if (!grid) return;
	var gx = grid.x,
		gy = grid.y;
	if (currentAction === 'place') {
		// Place or change block of the selected type
		if (!worldGrid[gy][gx]) {
			// Place new block
			worldGrid[gy][gx] = currentBlockType;
			var block = new Block();
			block.setType(currentBlockType);
			block.x = gridOffsetX + gx * BLOCK_SIZE + BLOCK_SIZE / 2;
			block.y = gridOffsetY + gy * BLOCK_SIZE + BLOCK_SIZE / 2;
			game.addChild(block);
			blockObjects[gy][gx] = block;
		} else {
			// Change existing block type
			worldGrid[gy][gx] = currentBlockType;
			if (blockObjects[gy][gx]) {
				blockObjects[gy][gx].setType(currentBlockType);
			}
		}
	} else if (currentAction === 'remove') {
		if (worldGrid[gy][gx]) {
			// Remove block
			worldGrid[gy][gx] = null;
			if (blockObjects[gy][gx]) {
				blockObjects[gy][gx].destroy();
				blockObjects[gy][gx] = null;
			}
		}
	}
};
// --- Voxel 2D Sandbox Setup ---
// Grid size (number of blocks)
var GRID_WIDTH = 20;
var GRID_HEIGHT = 15;
// Block size in pixels (auto from asset, but fallback to 100)
var BLOCK_SIZE = 100;
// 2D array to store block types, initialize with 'dirt' for a flat world
var worldGrid = [];
for (var y = 0; y < GRID_HEIGHT; y++) {
	worldGrid[y] = [];
	for (var x = 0; x < GRID_WIDTH; x++) {
		if (y === Math.floor(GRID_HEIGHT / 2)) {
			worldGrid[y][x] = 'grass';
		} else if (y > Math.floor(GRID_HEIGHT / 2) && y < GRID_HEIGHT - 2) {
			worldGrid[y][x] = 'dirt';
		} else if (y >= GRID_HEIGHT - 2) {
			worldGrid[y][x] = 'stone';
		} else {
			worldGrid[y][x] = null;
		}
	}
}
// Store block objects for easy access/removal
var blockObjects = [];
// Center the grid in the game area
var gridOffsetX = (2048 - GRID_WIDTH * BLOCK_SIZE) / 2;
var gridOffsetY = (2732 - GRID_HEIGHT * BLOCK_SIZE) / 2;
// Render the initial world
for (var y = 0; y < GRID_HEIGHT; y++) {
	blockObjects[y] = [];
	for (var x = 0; x < GRID_WIDTH; x++) {
		if (worldGrid[y][x]) {
			var block = new Block();
			block.setType(worldGrid[y][x]);
			block.x = gridOffsetX + x * BLOCK_SIZE + BLOCK_SIZE / 2;
			block.y = gridOffsetY + y * BLOCK_SIZE + BLOCK_SIZE / 2;
			game.addChild(block);
			blockObjects[y][x] = block;
		} else {
			blockObjects[y][x] = null;
		}
	}
}

===================================================================
--- original.js
+++ change.js
@@ -131,17 +131,24 @@
 	if (!grid) return;
 	var gx = grid.x,
 		gy = grid.y;
 	if (currentAction === 'place') {
+		// Place or change block of the selected type
 		if (!worldGrid[gy][gx]) {
-			// Place a block of the selected type
+			// Place new block
 			worldGrid[gy][gx] = currentBlockType;
 			var block = new Block();
 			block.setType(currentBlockType);
 			block.x = gridOffsetX + gx * BLOCK_SIZE + BLOCK_SIZE / 2;
 			block.y = gridOffsetY + gy * BLOCK_SIZE + BLOCK_SIZE / 2;
 			game.addChild(block);
 			blockObjects[gy][gx] = block;
+		} else {
+			// Change existing block type
+			worldGrid[gy][gx] = currentBlockType;
+			if (blockObjects[gy][gx]) {
+				blockObjects[gy][gx].setType(currentBlockType);
+			}
 		}
 	} else if (currentAction === 'remove') {
 		if (worldGrid[gy][gx]) {
 			// Remove block