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

/**** 
* Classes
****/ 
// Ball class
var Ball = Container.expand(function () {
	var self = Container.call(this);
	// Ball properties
	self.size = 1; // 1-9
	self.radius = 60; // default, will be set in init
	self.vx = 0;
	self.vy = 0;
	self.isMerging = false; // Prevent double merge
	// Attach asset based on size
	self.setSize = function (size) {
		self.size = size;
		// Remove previous asset if any
		if (self.ballAsset) {
			self.removeChild(self.ballAsset);
		}
		var assetId = 'ball' + size;
		self.ballAsset = self.attachAsset(assetId, {
			anchorX: 0.5,
			anchorY: 0.5
		});
		self.radius = self.ballAsset.width / 2;
	};
	// Set initial size
	self.setSize(1);
	// For merge animation
	self.flash = function () {
		tween(self.ballAsset, {
			scaleX: 1.2,
			scaleY: 1.2
		}, {
			duration: 120,
			easing: tween.easeOut,
			onFinish: function onFinish() {
				tween(self.ballAsset, {
					scaleX: 1,
					scaleY: 1
				}, {
					duration: 120,
					easing: tween.easeIn
				});
			}
		});
	};
	// For showing value
	self.showValue = function () {
		if (self.valueText) {
			self.removeChild(self.valueText);
		}
		self.valueText = new Text2('' + self.size, {
			size: Math.max(60, self.radius),
			fill: 0xFFFFFF
		});
		self.valueText.anchor.set(0.5, 0.5);
		self.addChild(self.valueText);
	};
	self.showValue();
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x222831
});

/**** 
* Game Code
****/ 
// Game constants
// Ball shapes for different sizes (size1, size2, size3, size4, size5, size6, size7, size8, size9)
// Sound for merging
var GAME_WIDTH = 2048;
var GAME_HEIGHT = 2732;
var BALL_MIN_SIZE = 1;
var BALL_MAX_SIZE = 12; // Now only up to 3 new big balls (ball10, ball11, ball12)
var BALL_LIMIT = 16; // Max balls allowed on screen before game over
// var INIT_BALLS = 9; // No longer needed, no initial balls
var GRAVITY = 1.2;
var BOUNCE = 0.7;
var FRICTION = 0.995;
var WALL_BOUNCE = 0.8;
var SPAWN_Y = 180; // y position for new balls
// Ball array
var balls = [];
// Score
var score = 0;
var scoreTxt = new Text2('0', {
	size: 120,
	fill: "#fff"
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// Next ball preview
var nextBallSize = BALL_MIN_SIZE + Math.floor(Math.random() * 4); // Only 1-4
var nextBallPreview = LK.getAsset('ball' + nextBallSize, {
	anchorX: 0.5,
	anchorY: 0.5,
	x: GAME_WIDTH / 2,
	y: SPAWN_Y - 100
});
game.addChild(nextBallPreview);
// Helper: get random ball size (only 1-4 for spawn)
function getRandomBallSize() {
	// Weighted random: 1: 45%, 2: 30%, 3: 15%, 4: 10%
	var r = Math.random();
	if (r < 0.45) return 1;
	if (r < 0.75) return 2;
	if (r < 0.90) return 3;
	return 4;
}
// Helper: clamp
function clamp(val, min, max) {
	return Math.max(min, Math.min(max, val));
}
// Helper: distance squared
function dist2(a, b) {
	var dx = a.x - b.x;
	var dy = a.y - b.y;
	return dx * dx + dy * dy;
}
// Helper: check overlap
function isOverlapping(ballA, ballB) {
	var rSum = ballA.radius + ballB.radius;
	return dist2(ballA, ballB) < rSum * rSum - 1;
}
// Helper: resolve overlap
function resolveOverlap(ballA, ballB) {
	var dx = ballB.x - ballA.x;
	var dy = ballB.y - ballA.y;
	var dist = Math.sqrt(dx * dx + dy * dy);
	if (dist === 0) {
		// Random nudge
		dx = 1;
		dy = 0;
		dist = 1;
	}
	var overlap = ballA.radius + ballB.radius - dist;
	if (overlap > 0) {
		var pushX = dx / dist * (overlap / 2);
		var pushY = dy / dist * (overlap / 2);
		ballA.x -= pushX;
		ballA.y -= pushY;
		ballB.x += pushX;
		ballB.y += pushY;
	}
}
// Helper: merge balls
function mergeBalls(ballA, ballB) {
	// Only merge if both are not merging and same size
	if (ballA.isMerging || ballB.isMerging) return false;
	if (ballA.size !== ballB.size) return false;
	ballA.isMerging = true;
	ballB.isMerging = true;
	// New ball at average position
	var newBall = new Ball();
	var newSize = clamp(ballA.size + 1, BALL_MIN_SIZE, BALL_MAX_SIZE);
	newBall.setSize(newSize);
	newBall.x = (ballA.x + ballB.x) / 2;
	newBall.y = (ballA.y + ballB.y) / 2;
	newBall.vx = (ballA.vx + ballB.vx) / 2;
	newBall.vy = (ballA.vy + ballB.vy) / 2;
	newBall.showValue();
	newBall.flash();
	// Remove old balls
	ballA.destroy();
	ballB.destroy();
	var idxA = balls.indexOf(ballA);
	var idxB = balls.indexOf(ballB);
	if (idxA !== -1) balls.splice(idxA, 1);
	if (idxB !== -1) balls.splice(balls.indexOf(ballB), 1); // index may have shifted
	// Add new ball
	balls.push(newBall);
	game.addChild(newBall);
	// Play merge sound
	LK.getSound('merge').play();
	// Add score
	score += Math.pow(2, newSize);
	scoreTxt.setText(score);
	// Animate
	newBall.flash();
	// Feature 9: Shake nearby balls after merge
	var SHAKE_RADIUS = newBall.radius * 3;
	for (var i = 0; i < balls.length; i++) {
		var b = balls[i];
		if (b !== newBall && !b.isMerging) {
			var dx = b.x - newBall.x;
			var dy = b.y - newBall.y;
			var dist = Math.sqrt(dx * dx + dy * dy);
			if (dist < SHAKE_RADIUS) {
				// Give a small random velocity burst
				var angle = Math.atan2(dy, dx);
				var force = 10 + Math.random() * 10;
				b.vx += Math.cos(angle) * force * (0.7 + 0.6 * Math.random());
				b.vy += Math.sin(angle) * force * (0.7 + 0.6 * Math.random());
			}
		}
	}
	return newBall;
}
// Spawn a ball at (x, y) with given size
function spawnBall(x, y, size) {
	var ball = new Ball();
	ball.setSize(size);
	ball.x = clamp(x, ball.radius, GAME_WIDTH - ball.radius);
	ball.y = y;
	ball.vx = (Math.random() - 0.5) * 16;
	ball.vy = 0;
	ball.showValue();
	balls.push(ball);
	game.addChild(ball);
	return ball;
}
// No initial balls function needed
// Drag and drop for new balls
var isDragging = false;
var dragX = GAME_WIDTH / 2;
var dragBall = null;
// Show drag preview
var dragPreview = null;
function showDragPreview(x) {
	if (!dragPreview) {
		dragPreview = LK.getAsset('ball' + nextBallSize, {
			anchorX: 0.5,
			anchorY: 0.5,
			x: x,
			y: SPAWN_Y
		});
		game.addChild(dragPreview);
	}
	dragPreview.x = clamp(x, dragPreview.width / 2, GAME_WIDTH - dragPreview.width / 2);
	dragPreview.y = SPAWN_Y;
}
function hideDragPreview() {
	if (dragPreview) {
		dragPreview.destroy();
		dragPreview = null;
	}
}
// Handle touch/mouse down
game.down = function (x, y, obj) {
	// Only allow drop in top 1/3 of screen
	if (y > GAME_HEIGHT / 2) return;
	isDragging = true;
	dragX = clamp(x, 100, GAME_WIDTH - 100);
	showDragPreview(dragX);
};
// Handle move
game.move = function (x, y, obj) {
	if (isDragging) {
		dragX = clamp(x, 100, GAME_WIDTH - 100);
		showDragPreview(dragX);
	}
};
// Handle up (drop ball)
game.up = function (x, y, obj) {
	if (isDragging) {
		isDragging = false;
		hideDragPreview();
		// Drop ball at dragX
		spawnBall(dragX, SPAWN_Y, nextBallSize);
		// Next ball
		nextBallSize = getRandomBallSize();
		// Update preview
		if (nextBallPreview) {
			nextBallPreview.destroy();
		}
		nextBallPreview = LK.getAsset('ball' + nextBallSize, {
			anchorX: 0.5,
			anchorY: 0.5,
			x: GAME_WIDTH / 2,
			y: SPAWN_Y - 100
		});
		game.addChild(nextBallPreview);
	}
};
// Main update loop
game.update = function () {
	// Physics for each ball
	for (var i = 0; i < balls.length; i++) {
		var ball = balls[i];
		// Gravity
		ball.vy += GRAVITY;
		// Move
		ball.x += ball.vx;
		ball.y += ball.vy;
		// Wall collision
		if (ball.x - ball.radius < 0) {
			ball.x = ball.radius;
			ball.vx = -ball.vx * WALL_BOUNCE;
		}
		if (ball.x + ball.radius > GAME_WIDTH) {
			ball.x = GAME_WIDTH - ball.radius;
			ball.vx = -ball.vx * WALL_BOUNCE;
		}
		// Floor
		if (ball.y + ball.radius > GAME_HEIGHT) {
			ball.y = GAME_HEIGHT - ball.radius;
			ball.vy = -ball.vy * BOUNCE;
			ball.vx *= FRICTION;
			// Stop tiny bounces
			if (Math.abs(ball.vy) < 2) ball.vy = 0;
		}
		// Ceiling
		if (ball.y - ball.radius < 0) {
			ball.y = ball.radius;
			ball.vy = -ball.vy * BOUNCE;
		}
		// Friction
		ball.vx *= FRICTION;
		ball.vy *= FRICTION;
	}
	// Ball-ball collision and merging
	for (var i = 0; i < balls.length; i++) {
		for (var j = i + 1; j < balls.length; j++) {
			var a = balls[i],
				b = balls[j];
			if (isOverlapping(a, b)) {
				// If same size, merge
				if (a.size === b.size && !a.isMerging && !b.isMerging) {
					mergeBalls(a, b);
					break; // balls array changed, restart
				} else {
					// Elastic collision
					resolveOverlap(a, b);
					// Simple velocity swap
					var dx = b.x - a.x;
					var dy = b.y - a.y;
					var dist = Math.sqrt(dx * dx + dy * dy);
					if (dist > 0) {
						var nx = dx / dist,
							ny = dy / dist;
						var p = 2 * (a.vx * nx + a.vy * ny - b.vx * nx - b.vy * ny) / 2;
						a.vx = a.vx - p * nx;
						a.vy = a.vy - p * ny;
						b.vx = b.vx + p * nx;
						b.vy = b.vy + p * ny;
					}
				}
			}
		}
	}
	// Remove balls marked for destroy (already handled in mergeBalls)
	// Check for game over
	if (balls.length > BALL_LIMIT) {
		LK.effects.flashScreen(0xff0000, 800);
		LK.showGameOver();
	}
	// Optionally: win condition (e.g. create a ball of size 12)
	for (var i = 0; i < balls.length; i++) {
		if (balls[i].size === 12) {
			LK.effects.flashScreen(0xffff00, 1000);
			LK.showYouWin();
			break;
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -110,9 +110,14 @@
 });
 game.addChild(nextBallPreview);
 // Helper: get random ball size (only 1-4 for spawn)
 function getRandomBallSize() {
-	return BALL_MIN_SIZE + Math.floor(Math.random() * 4);
+	// Weighted random: 1: 45%, 2: 30%, 3: 15%, 4: 10%
+	var r = Math.random();
+	if (r < 0.45) return 1;
+	if (r < 0.75) return 2;
+	if (r < 0.90) return 3;
+	return 4;
 }
 // Helper: clamp
 function clamp(val, min, max) {
 	return Math.max(min, Math.min(max, val));
@@ -182,8 +187,25 @@
 	score += Math.pow(2, newSize);
 	scoreTxt.setText(score);
 	// Animate
 	newBall.flash();
+	// Feature 9: Shake nearby balls after merge
+	var SHAKE_RADIUS = newBall.radius * 3;
+	for (var i = 0; i < balls.length; i++) {
+		var b = balls[i];
+		if (b !== newBall && !b.isMerging) {
+			var dx = b.x - newBall.x;
+			var dy = b.y - newBall.y;
+			var dist = Math.sqrt(dx * dx + dy * dy);
+			if (dist < SHAKE_RADIUS) {
+				// Give a small random velocity burst
+				var angle = Math.atan2(dy, dx);
+				var force = 10 + Math.random() * 10;
+				b.vx += Math.cos(angle) * force * (0.7 + 0.6 * Math.random());
+				b.vy += Math.sin(angle) * force * (0.7 + 0.6 * Math.random());
+			}
+		}
+	}
 	return newBall;
 }
 // Spawn a ball at (x, y) with given size
 function spawnBall(x, y, size) {