===================================================================
--- original.js
+++ change.js
@@ -404,35 +404,8 @@
 
 /**** 
 * Game Code
 ****/ 
-// Simple Set class to fix the constructor error
-var Set = function Set() {
-	var self = this;
-	self.items = {};
-	self.has = function (value) {
-		return self.items.hasOwnProperty(value);
-	};
-	self.add = function (value) {
-		self.items[value] = true;
-	};
-	self["delete"] = function (value) {
-		if (self.has(value)) {
-			delete self.items[value];
-			return true;
-		}
-		return false;
-	};
-	self.clear = function () {
-		self.items = {};
-	};
-	self.size = function () {
-		return Object.keys(self.items).length;
-	};
-	self.values = function () {
-		return Object.keys(self.items);
-	};
-};
 function _slicedToArray(r, e) {
 	return _arrayWithHoles(r) || _iterableToArrayLimit(r, e) || _unsupportedIterableToArray(r, e) || _nonIterableRest();
 }
 function _nonIterableRest() {
@@ -495,8 +468,19 @@
 	if (Array.isArray(r)) {
 		return r;
 	}
 }
+var SimpleSet = function SimpleSet() {
+	this.items = {};
+	this.has = function (item) {
+		return this.items.hasOwnProperty(item);
+	};
+	this.add = function (item) {
+		if (!this.has(item)) {
+			this.items[item] = true;
+		}
+	};
+};
 var PuzzleManager = function PuzzleManager() {
 	var self = this;
 	// Properties
 	self.currentLevel = 1;
@@ -564,16 +548,20 @@
 		// Convert screen coordinates to grid coordinates
 		if (!isPlaying) {
 			return;
 		}
-		var gridX = Math.floor((x - (gridBoard.x - gridBoard.width / 2 + tileSize / 2)) / tileSize);
-		var gridY = Math.floor((y - (gridBoard.y - gridBoard.height / 2 + tileSize / 2)) / tileSize);
+		// Adjust coordinate calculation to use grid board position and size
+		var boardX = gridBoard.x - gridBoard.width / 2;
+		var boardY = gridBoard.y - gridBoard.height / 2;
+		var gridX = Math.floor((x - boardX) / tileSize);
+		var gridY = Math.floor((y - boardY) / tileSize);
+		log("Grid coordinates:", gridX, gridY);
 		// Check if coordinates are within grid
 		if (gridX >= 0 && gridX < self.gridSize && gridY >= 0 && gridY < self.gridSize) {
 			var tile = self.grid[gridX][gridY];
 			var key = gridX + ',' + gridY;
 			// Check if tile exists, is not empty, not start/end, and not fixed
-			if (tile && tile.type !== 'empty' && tile.type !== 'start' && tile.type !== 'end' && !self.levelConfigs[self.currentLevel].fixedTiles.includes(key)) {
+			if (tile && tile.type !== 'empty' && tile.type !== 'start' && tile.type !== 'end' && (!self.levelConfigs[self.currentLevel].fixedTiles || !self.levelConfigs[self.currentLevel].fixedTiles.includes(key))) {
 				self.selectedTile = {
 					x: gridX,
 					y: gridY,
 					tile: tile
@@ -658,9 +646,8 @@
 		self.waterFlowing = false;
 		self.initPuzzle();
 	};
 	self.checkWinCondition = function () {
-		log("Checking win condition...");
 		// Find start tile
 		var startTile = null;
 		var startX = 0;
 		var startY = 0;
@@ -678,34 +665,40 @@
 				break;
 			}
 		}
 		if (!startTile) {
-			log("No start tile found.");
+			log("No start tile found");
 			return false;
 		}
 		// Check if there's a valid path from start to end
-		var result = self.canReachEnd(startX, startY, new Set());
+		var result = self.canReachEnd(startX, startY, new SimpleSet());
 		log("Win condition result:", result);
 		return result;
 	};
 	self.canReachEnd = function (x, y, visited) {
+		log("Checking position:", x, y);
 		// Check bounds
 		if (x < 0 || x >= self.gridSize || y < 0 || y >= self.gridSize) {
+			log("Out of bounds");
 			return false;
 		}
 		// Get current tile
 		var tile = self.grid[x][y];
 		if (!tile) {
+			log("No tile at position");
 			return false;
 		}
 		// Mark as visited
 		var key = x + ',' + y;
 		if (visited.has(key)) {
+			log("Already visited");
 			return false;
 		}
 		visited.add(key);
+		log("Checking tile type:", tile.type);
 		// If we reached the end tile, success!
 		if (tile.type === 'end') {
+			log("Found end tile!");
 			return true;
 		}
 		// Get possible directions based on tile type and rotation
 		var directions = [];
@@ -719,24 +712,30 @@
 			case 'straightPipeH':
 				directions.push([1, 0], [-1, 0]); // Left and right
 				break;
 			case 'cornerPipe':
-				if (tile.rotation === 'up') {
-					directions.push([1, 0], [0, -1]); // Right and up
-				} else if (tile.rotation === 'right') {
-					directions.push([1, 0], [0, 1]); // Right and down
-				} else if (tile.rotation === 'down') {
-					directions.push([-1, 0], [0, 1]); // Left and down
-				} else {
-					directions.push([-1, 0], [0, -1]); // Left and up
+				switch (tile.rotation) {
+					case 'up':
+						directions.push([1, 0], [0, -1]); // Right and up
+						break;
+					case 'right':
+						directions.push([1, 0], [0, 1]); // Right and down
+						break;
+					case 'down':
+						directions.push([-1, 0], [0, 1]); // Left and down
+						break;
+					default:
+						// left
+						directions.push([-1, 0], [0, -1]); // Left and up
+						break;
 				}
 				break;
 		}
+		log("Possible directions:", directions);
 		// Try each direction
-		for (var _i = 0, _directions = directions; _i < _directions.length; _i++) {
-			var _directions$_i = _slicedToArray(_directions[_i], 2),
-				dx = _directions$_i[0],
-				dy = _directions$_i[1];
+		for (var i = 0; i < directions.length; i++) {
+			var dx = directions[i][0];
+			var dy = directions[i][1];
 			if (self.canReachEnd(x + dx, y + dy, visited)) {
 				return true;
 			}
 		}