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

/**** 
* Classes
****/ 
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdGraphics = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.velocityX = 0;
	self.velocityY = 0;
	self.launched = false;
	self.gravity = 0.3;
	self.bounce = 0.3;
	self.update = function () {
		if (self.launched) {
			self.velocityY += self.gravity;
			self.x += self.velocityX;
			self.y += self.velocityY;
			// Ground collision
			if (self.y > 2600) {
				self.y = 2600;
				self.velocityY *= -self.bounce;
				self.velocityX *= 0.8;
				if (Math.abs(self.velocityY) < 2) {
					self.velocityY = 0;
				}
			}
			// Side boundaries
			if (self.x < 0 || self.x > 2048) {
				self.velocityX *= -self.bounce;
			}
		}
	};
	self.launch = function (velX, velY) {
		self.launched = true;
		self.velocityX = velX;
		self.velocityY = velY;
		LK.getSound('launch').play();
	};
	return self;
});
var Block = Container.expand(function (type) {
	var self = Container.call(this);
	var assetName = type + 'Block';
	var blockGraphics = self.attachAsset(assetName, {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.type = type;
	self.health = type === 'wood' ? 50 : type === 'stone' ? 100 : 30; // ice is weakest
	self.destroyed = false;
	// Physics properties
	self.velocityX = 0;
	self.velocityY = 0;
	self.gravity = 0.3;
	self.bounce = 0.4;
	self.friction = 0.8;
	self.mass = type === 'stone' ? 3 : type === 'wood' ? 2 : 1; // ice is lightest
	self.isStatic = true; // blocks start as static until hit
	self.update = function () {
		if (!self.isStatic && !self.destroyed) {
			// Apply gravity
			self.velocityY += self.gravity;
			// Apply velocity
			self.x += self.velocityX;
			self.y += self.velocityY;
			// Ground collision
			if (self.y > 2580) {
				// account for block height
				self.y = 2580;
				self.velocityY *= -self.bounce;
				self.velocityX *= self.friction;
				if (Math.abs(self.velocityY) < 1) {
					self.velocityY = 0;
					self.isStatic = true; // become static again when settled
				}
			}
			// Side boundaries
			if (self.x < 60 || self.x > 1988) {
				// account for block width
				self.velocityX *= -self.bounce;
			}
			// Friction when moving slowly
			if (Math.abs(self.velocityX) < 0.5 && Math.abs(self.velocityY) < 0.5) {
				self.velocityX *= 0.9;
			}
		}
	};
	self.applyForce = function (forceX, forceY) {
		self.isStatic = false; // become dynamic when force is applied
		self.velocityX += forceX / self.mass;
		self.velocityY += forceY / self.mass;
	};
	self.takeDamage = function (damage) {
		self.health -= damage;
		if (self.health <= 0 && !self.destroyed) {
			self.destroyed = true;
			LK.effects.flashObject(self, 0xff0000, 200);
			LK.getSound('hit').play();
			LK.setScore(LK.getScore() + 10);
			scoreText.setText(LK.getScore());
		}
	};
	return self;
});
var Pig = Container.expand(function () {
	var self = Container.call(this);
	var pigGraphics = self.attachAsset('pig', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.health = 100;
	self.destroyed = false;
	self.takeDamage = function (damage) {
		self.health -= damage;
		if (self.health <= 0 && !self.destroyed) {
			self.destroyed = true;
			LK.effects.flashObject(self, 0xffff00, 300);
			LK.getSound('destroy').play();
			LK.setScore(LK.getScore() + 100);
			scoreText.setText(LK.getScore());
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87CEEB // Sky blue background
});

/**** 
* Game Code
****/ 
// Game variables
var birds = [];
var pigs = [];
var blocks = [];
var currentBird = null;
var slingshot = null;
var isDragging = false;
var trajectoryDots = [];
var slingshotX = 200;
var slingshotY = 2400;
var birdsRemaining = 8;
var level = 1;
// UI Elements
var scoreText = new Text2('Score: 0', {
	size: 60,
	fill: 0xFFFFFF
});
scoreText.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreText);
var birdsText = new Text2('Birds: 8', {
	size: 50,
	fill: 0xFFFFFF
});
birdsText.anchor.set(0, 0);
birdsText.x = 100;
birdsText.y = 100;
LK.gui.topLeft.addChild(birdsText);
var levelText = new Text2('Level: 1', {
	size: 50,
	fill: 0xFFFFFF
});
levelText.anchor.set(1, 0);
levelText.x = -100;
levelText.y = 100;
LK.gui.topRight.addChild(levelText);
// Create ground
var ground = game.addChild(LK.getAsset('ground', {
	anchorX: 0,
	anchorY: 1,
	x: 0,
	y: 2732
}));
// Create clouds for background atmosphere
var cloud1 = game.addChild(LK.getAsset('cloud', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 300,
	y: 400,
	alpha: 0.8
}));
var cloud2 = game.addChild(LK.getAsset('cloud', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 800,
	y: 300,
	alpha: 0.7
}));
var cloud3 = game.addChild(LK.getAsset('cloud', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 1400,
	y: 450,
	alpha: 0.6
}));
var cloud4 = game.addChild(LK.getAsset('cloud', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 1800,
	y: 350,
	alpha: 0.8
}));
// Create slingshot
slingshot = game.addChild(LK.getAsset('slingshot', {
	anchorX: 0.5,
	anchorY: 1,
	x: slingshotX,
	y: slingshotY
}));
// Create level structures
function createLevel1() {
	// Create pigs
	var pig1 = game.addChild(new Pig());
	pig1.x = 1400;
	pig1.y = 2300;
	pigs.push(pig1);
	var pig2 = game.addChild(new Pig());
	pig2.x = 1600;
	pig2.y = 2200;
	pigs.push(pig2);
	// Additional pigs
	var pig3 = game.addChild(new Pig());
	pig3.x = 1250;
	pig3.y = 2300;
	pigs.push(pig3);
	var pig4 = game.addChild(new Pig());
	pig4.x = 1400;
	pig4.y = 2100;
	pigs.push(pig4);
	var pig5 = game.addChild(new Pig());
	pig5.x = 1750;
	pig5.y = 2200;
	pigs.push(pig5);
	// Create structure
	var block1 = game.addChild(new Block('wood'));
	block1.x = 1300;
	block1.y = 2350;
	blocks.push(block1);
	var block2 = game.addChild(new Block('wood'));
	block2.x = 1500;
	block2.y = 2350;
	blocks.push(block2);
	var block3 = game.addChild(new Block('stone'));
	block3.x = 1400;
	block3.y = 2250;
	blocks.push(block3);
	var block4 = game.addChild(new Block('ice'));
	block4.x = 1600;
	block4.y = 2300;
	blocks.push(block4);
	// Additional foundation blocks
	var block5 = game.addChild(new Block('wood'));
	block5.x = 1200;
	block5.y = 2350;
	blocks.push(block5);
	var block6 = game.addChild(new Block('wood'));
	block6.x = 1700;
	block6.y = 2350;
	blocks.push(block6);
	// Upper level blocks
	var block7 = game.addChild(new Block('ice'));
	block7.x = 1350;
	block7.y = 2200;
	blocks.push(block7);
	var block8 = game.addChild(new Block('ice'));
	block8.x = 1450;
	block8.y = 2200;
	blocks.push(block8);
	// Top blocks
	var block9 = game.addChild(new Block('stone'));
	block9.x = 1400;
	block9.y = 2150;
	blocks.push(block9);
	// Side tower blocks
	var block10 = game.addChild(new Block('wood'));
	block10.x = 1750;
	block10.y = 2300;
	blocks.push(block10);
	var block11 = game.addChild(new Block('ice'));
	block11.x = 1750;
	block11.y = 2250;
	blocks.push(block11);
}
// Initialize first bird
function createNewBird() {
	if (birdsRemaining > 0) {
		currentBird = game.addChild(new Bird());
		currentBird.x = slingshotX;
		currentBird.y = slingshotY - 100;
		birds.push(currentBird);
	}
}
// Trajectory calculation
function calculateTrajectory(startX, startY, velX, velY) {
	var dots = [];
	var x = startX;
	var y = startY;
	var vx = velX;
	var vy = velY;
	var gravity = 0.3;
	for (var i = 0; i < 50; i += 3) {
		dots.push({
			x: x,
			y: y
		});
		vx *= 0.99;
		vy += gravity;
		x += vx * 3;
		y += vy * 3;
		if (y > 2600 || x > 2048) break;
	}
	return dots;
}
// Clear trajectory dots
function clearTrajectory() {
	for (var i = 0; i < trajectoryDots.length; i++) {
		trajectoryDots[i].destroy();
	}
	trajectoryDots = [];
}
// Show trajectory dots
function showTrajectory(dots) {
	clearTrajectory();
	for (var i = 0; i < dots.length; i++) {
		var dot = game.addChild(LK.getAsset('trajectory', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: dots[i].x,
			y: dots[i].y,
			alpha: 0.5
		}));
		trajectoryDots.push(dot);
	}
}
// Check collisions
function checkCollisions() {
	for (var i = 0; i < birds.length; i++) {
		var bird = birds[i];
		if (!bird.launched) continue;
		// Check bird vs pigs
		for (var j = 0; j < pigs.length; j++) {
			var pig = pigs[j];
			if (!pig.destroyed && bird.intersects(pig)) {
				var damage = Math.abs(bird.velocityX) + Math.abs(bird.velocityY);
				pig.takeDamage(damage * 2);
			}
		}
		// Check bird vs blocks
		for (var k = 0; k < blocks.length; k++) {
			var block = blocks[k];
			if (!block.destroyed && bird.intersects(block)) {
				var damage = Math.abs(bird.velocityX) + Math.abs(bird.velocityY);
				block.takeDamage(damage);
				// Apply physics force to block based on bird's velocity and mass
				var forceX = bird.velocityX * 0.8;
				var forceY = bird.velocityY * 0.8;
				block.applyForce(forceX, forceY);
				bird.velocityX *= 0.5;
				bird.velocityY *= 0.5;
			}
		}
		// Check block vs block collisions
		for (var m = 0; m < blocks.length; m++) {
			var block1 = blocks[m];
			if (block1.destroyed || block1.isStatic) continue;
			for (var n = m + 1; n < blocks.length; n++) {
				var block2 = blocks[n];
				if (block2.destroyed) continue;
				if (block1.intersects(block2)) {
					// Calculate collision response
					var dx = block2.x - block1.x;
					var dy = block2.y - block1.y;
					var distance = Math.sqrt(dx * dx + dy * dy);
					if (distance > 0) {
						// Normalize collision vector
						dx /= distance;
						dy /= distance;
						// Separate blocks
						var overlap = (block1.width + block2.width) / 2 - distance;
						if (overlap > 0) {
							block1.x -= dx * overlap * 0.5;
							block1.y -= dy * overlap * 0.5;
							block2.x += dx * overlap * 0.5;
							block2.y += dy * overlap * 0.5;
						}
						// Exchange velocities based on mass
						var totalMass = block1.mass + block2.mass;
						var v1 = block1.velocityX * dx + block1.velocityY * dy;
						var v2 = block2.velocityX * dx + block2.velocityY * dy;
						var newV1 = ((block1.mass - block2.mass) * v1 + 2 * block2.mass * v2) / totalMass;
						var newV2 = ((block2.mass - block1.mass) * v2 + 2 * block1.mass * v1) / totalMass;
						block1.velocityX += (newV1 - v1) * dx * 0.8;
						block1.velocityY += (newV1 - v1) * dy * 0.8;
						if (!block2.isStatic) {
							block2.velocityX += (newV2 - v2) * dx * 0.8;
							block2.velocityY += (newV2 - v2) * dy * 0.8;
						} else {
							// Make static block dynamic if hit hard enough
							var impact = Math.abs(newV1 - v1);
							if (impact > 2) {
								block2.applyForce((newV2 - v2) * dx * block2.mass, (newV2 - v2) * dy * block2.mass);
							}
						}
					}
				}
			}
		}
	}
}
// Check win condition
function checkWinCondition() {
	var allPigsDestroyed = true;
	for (var i = 0; i < pigs.length; i++) {
		if (!pigs[i].destroyed) {
			allPigsDestroyed = false;
			break;
		}
	}
	if (allPigsDestroyed) {
		if (level === 1) {
			// Progress to level 2
			LK.setTimeout(function () {
				level = 2;
				levelText.setText('Level: ' + level);
				birdsRemaining = 8;
				birdsText.setText('Birds: ' + birdsRemaining);
				// Clear existing objects
				for (var i = 0; i < blocks.length; i++) {
					blocks[i].destroy();
				}
				blocks = [];
				for (var j = 0; j < pigs.length; j++) {
					pigs[j].destroy();
				}
				pigs = [];
				for (var k = 0; k < birds.length; k++) {
					birds[k].destroy();
				}
				birds = [];
				currentBird = null;
				// Initialize level 2
				initializeLevel();
				createNewBird();
			}, 1000);
		} else if (level === 2) {
			// Progress to level 3
			LK.setTimeout(function () {
				level = 3;
				levelText.setText('Level: ' + level);
				birdsRemaining = 8;
				birdsText.setText('Birds: ' + birdsRemaining);
				// Clear existing objects
				for (var i = 0; i < blocks.length; i++) {
					blocks[i].destroy();
				}
				blocks = [];
				for (var j = 0; j < pigs.length; j++) {
					pigs[j].destroy();
				}
				pigs = [];
				for (var k = 0; k < birds.length; k++) {
					birds[k].destroy();
				}
				birds = [];
				currentBird = null;
				// Initialize level 3
				initializeLevel();
				createNewBird();
			}, 1000);
		} else if (level === 3) {
			// Progress to level 4
			LK.setTimeout(function () {
				level = 4;
				levelText.setText('Level: ' + level);
				birdsRemaining = 8;
				birdsText.setText('Birds: ' + birdsRemaining);
				// Clear existing objects
				for (var i = 0; i < blocks.length; i++) {
					blocks[i].destroy();
				}
				blocks = [];
				for (var j = 0; j < pigs.length; j++) {
					pigs[j].destroy();
				}
				pigs = [];
				for (var k = 0; k < birds.length; k++) {
					birds[k].destroy();
				}
				birds = [];
				currentBird = null;
				// Initialize level 4
				initializeLevel();
				createNewBird();
			}, 1000);
		} else if (level === 4) {
			// Game completed
			LK.setTimeout(function () {
				LK.showYouWin();
			}, 1000);
		}
	} else if (birdsRemaining <= 0 && (!currentBird || currentBird.launched && Math.abs(currentBird.velocityX) < 1 && Math.abs(currentBird.velocityY) < 1)) {
		LK.setTimeout(function () {
			LK.showGameOver();
		}, 1000);
	}
}
// Game event handlers
game.down = function (x, y, obj) {
	if (currentBird && !currentBird.launched) {
		isDragging = true;
	}
};
game.move = function (x, y, obj) {
	if (isDragging && currentBird && !currentBird.launched) {
		var maxDistance = 150;
		var deltaX = slingshotX - x;
		var deltaY = slingshotY - 100 - y;
		var distance = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
		if (distance > maxDistance) {
			deltaX = deltaX / distance * maxDistance;
			deltaY = deltaY / distance * maxDistance;
		}
		currentBird.x = slingshotX - deltaX;
		currentBird.y = slingshotY - 100 - deltaY;
		// Show trajectory
		var velX = deltaX * 0.2;
		var velY = deltaY * 0.2;
		var trajectoryPoints = calculateTrajectory(currentBird.x, currentBird.y, velX, velY);
		showTrajectory(trajectoryPoints);
	}
};
game.up = function (x, y, obj) {
	if (isDragging && currentBird && !currentBird.launched) {
		isDragging = false;
		clearTrajectory();
		var deltaX = slingshotX - currentBird.x;
		var deltaY = slingshotY - 100 - currentBird.y;
		if (Math.abs(deltaX) > 5 || Math.abs(deltaY) > 5) {
			currentBird.launch(deltaX * 0.2, deltaY * 0.2);
			birdsRemaining--;
			birdsText.setText('Birds: ' + birdsRemaining);
			LK.setTimeout(function () {
				createNewBird();
			}, 2000);
		}
	}
};
// Main game update
game.update = function () {
	checkCollisions();
	checkWinCondition();
	// Remove destroyed objects
	for (var i = blocks.length - 1; i >= 0; i--) {
		if (blocks[i].destroyed) {
			blocks[i].destroy();
			blocks.splice(i, 1);
		}
	}
	for (var j = pigs.length - 1; j >= 0; j--) {
		if (pigs[j].destroyed) {
			pigs[j].alpha = Math.max(0, pigs[j].alpha - 0.02);
			if (pigs[j].alpha <= 0) {
				pigs[j].destroy();
				pigs.splice(j, 1);
			}
		}
	}
};
// Create level 2 structures
function createLevel2() {
	// Create more pigs for level 2
	var pig1 = game.addChild(new Pig());
	pig1.x = 1300;
	pig1.y = 2300;
	pigs.push(pig1);
	var pig2 = game.addChild(new Pig());
	pig2.x = 1500;
	pig2.y = 2300;
	pigs.push(pig2);
	var pig3 = game.addChild(new Pig());
	pig3.x = 1700;
	pig3.y = 2300;
	pigs.push(pig3);
	var pig4 = game.addChild(new Pig());
	pig4.x = 1400;
	pig4.y = 2150;
	pigs.push(pig4);
	var pig5 = game.addChild(new Pig());
	pig5.x = 1600;
	pig5.y = 2150;
	pigs.push(pig5);
	var pig6 = game.addChild(new Pig());
	pig6.x = 1500;
	pig6.y = 2000;
	pigs.push(pig6);
	// Create more complex structure for level 2
	// Base foundation
	var block1 = game.addChild(new Block('stone'));
	block1.x = 1250;
	block1.y = 2350;
	blocks.push(block1);
	var block2 = game.addChild(new Block('stone'));
	block2.x = 1350;
	block2.y = 2350;
	blocks.push(block2);
	var block3 = game.addChild(new Block('stone'));
	block3.x = 1450;
	block3.y = 2350;
	blocks.push(block3);
	var block4 = game.addChild(new Block('stone'));
	block4.x = 1550;
	block4.y = 2350;
	blocks.push(block4);
	var block5 = game.addChild(new Block('stone'));
	block5.x = 1650;
	block5.y = 2350;
	blocks.push(block5);
	var block6 = game.addChild(new Block('stone'));
	block6.x = 1750;
	block6.y = 2350;
	blocks.push(block6);
	// Second level
	var block7 = game.addChild(new Block('wood'));
	block7.x = 1300;
	block7.y = 2250;
	blocks.push(block7);
	var block8 = game.addChild(new Block('wood'));
	block8.x = 1400;
	block8.y = 2250;
	blocks.push(block8);
	var block9 = game.addChild(new Block('wood'));
	block9.x = 1500;
	block9.y = 2250;
	blocks.push(block9);
	var block10 = game.addChild(new Block('wood'));
	block10.x = 1600;
	block10.y = 2250;
	blocks.push(block10);
	var block11 = game.addChild(new Block('wood'));
	block11.x = 1700;
	block11.y = 2250;
	blocks.push(block11);
	// Third level
	var block12 = game.addChild(new Block('ice'));
	block12.x = 1350;
	block12.y = 2150;
	blocks.push(block12);
	var block13 = game.addChild(new Block('ice'));
	block13.x = 1450;
	block13.y = 2150;
	blocks.push(block13);
	var block14 = game.addChild(new Block('ice'));
	block14.x = 1550;
	block14.y = 2150;
	blocks.push(block14);
	var block15 = game.addChild(new Block('ice'));
	block15.x = 1650;
	block15.y = 2150;
	blocks.push(block15);
	// Top level
	var block16 = game.addChild(new Block('wood'));
	block16.x = 1400;
	block16.y = 2050;
	blocks.push(block16);
	var block17 = game.addChild(new Block('wood'));
	block17.x = 1500;
	block17.y = 2050;
	blocks.push(block17);
	var block18 = game.addChild(new Block('wood'));
	block18.x = 1600;
	block18.y = 2050;
	blocks.push(block18);
}
// Create level 3 structures
function createLevel3() {
	// Create simple structure with fewer pigs for easier level
	var pig1 = game.addChild(new Pig());
	pig1.x = 1400;
	pig1.y = 2300;
	pigs.push(pig1);
	var pig2 = game.addChild(new Pig());
	pig2.x = 1600;
	pig2.y = 2300;
	pigs.push(pig2);
	var pig3 = game.addChild(new Pig());
	pig3.x = 1500;
	pig3.y = 2150;
	pigs.push(pig3);
	// Simple structure for level 3
	// Base blocks
	var block1 = game.addChild(new Block('wood'));
	block1.x = 1350;
	block1.y = 2350;
	blocks.push(block1);
	var block2 = game.addChild(new Block('wood'));
	block2.x = 1450;
	block2.y = 2350;
	blocks.push(block2);
	var block3 = game.addChild(new Block('wood'));
	block3.x = 1550;
	block3.y = 2350;
	blocks.push(block3);
	var block4 = game.addChild(new Block('wood'));
	block4.x = 1650;
	block4.y = 2350;
	blocks.push(block4);
	// Upper blocks
	var block5 = game.addChild(new Block('ice'));
	block5.x = 1400;
	block5.y = 2250;
	blocks.push(block5);
	var block6 = game.addChild(new Block('ice'));
	block6.x = 1500;
	block6.y = 2250;
	blocks.push(block6);
	var block7 = game.addChild(new Block('ice'));
	block7.x = 1600;
	block7.y = 2250;
	blocks.push(block7);
	// Top block
	var block8 = game.addChild(new Block('stone'));
	block8.x = 1500;
	block8.y = 2200;
	blocks.push(block8);
}
// Create level 4 structures
function createLevel4() {
	// Create minimal structure with fewer blocks and pigs for easy final level
	var pig1 = game.addChild(new Pig());
	pig1.x = 1500;
	pig1.y = 2300;
	pigs.push(pig1);
	var pig2 = game.addChild(new Pig());
	pig2.x = 1500;
	pig2.y = 2200;
	pigs.push(pig2);
	// Minimal structure for level 4 - fewer blocks
	// Base blocks
	var block1 = game.addChild(new Block('ice'));
	block1.x = 1450;
	block1.y = 2350;
	blocks.push(block1);
	var block2 = game.addChild(new Block('ice'));
	block2.x = 1550;
	block2.y = 2350;
	blocks.push(block2);
	// Single upper block
	var block3 = game.addChild(new Block('wood'));
	block3.x = 1500;
	block3.y = 2250;
	blocks.push(block3);
}
// Initialize level based on current level
function initializeLevel() {
	if (level === 1) {
		createLevel1();
	} else if (level === 2) {
		createLevel2();
	} else if (level === 3) {
		createLevel3();
	} else if (level === 4) {
		createLevel4();
	}
}
// Initialize level
initializeLevel();
createNewBird();

===================================================================
--- original.js
+++ change.js
@@ -54,8 +54,50 @@
 	});
 	self.type = type;
 	self.health = type === 'wood' ? 50 : type === 'stone' ? 100 : 30; // ice is weakest
 	self.destroyed = false;
+	// Physics properties
+	self.velocityX = 0;
+	self.velocityY = 0;
+	self.gravity = 0.3;
+	self.bounce = 0.4;
+	self.friction = 0.8;
+	self.mass = type === 'stone' ? 3 : type === 'wood' ? 2 : 1; // ice is lightest
+	self.isStatic = true; // blocks start as static until hit
+	self.update = function () {
+		if (!self.isStatic && !self.destroyed) {
+			// Apply gravity
+			self.velocityY += self.gravity;
+			// Apply velocity
+			self.x += self.velocityX;
+			self.y += self.velocityY;
+			// Ground collision
+			if (self.y > 2580) {
+				// account for block height
+				self.y = 2580;
+				self.velocityY *= -self.bounce;
+				self.velocityX *= self.friction;
+				if (Math.abs(self.velocityY) < 1) {
+					self.velocityY = 0;
+					self.isStatic = true; // become static again when settled
+				}
+			}
+			// Side boundaries
+			if (self.x < 60 || self.x > 1988) {
+				// account for block width
+				self.velocityX *= -self.bounce;
+			}
+			// Friction when moving slowly
+			if (Math.abs(self.velocityX) < 0.5 && Math.abs(self.velocityY) < 0.5) {
+				self.velocityX *= 0.9;
+			}
+		}
+	};
+	self.applyForce = function (forceX, forceY) {
+		self.isStatic = false; // become dynamic when force is applied
+		self.velocityX += forceX / self.mass;
+		self.velocityY += forceY / self.mass;
+	};
 	self.takeDamage = function (damage) {
 		self.health -= damage;
 		if (self.health <= 0 && !self.destroyed) {
 			self.destroyed = true;
@@ -319,12 +361,62 @@
 			var block = blocks[k];
 			if (!block.destroyed && bird.intersects(block)) {
 				var damage = Math.abs(bird.velocityX) + Math.abs(bird.velocityY);
 				block.takeDamage(damage);
+				// Apply physics force to block based on bird's velocity and mass
+				var forceX = bird.velocityX * 0.8;
+				var forceY = bird.velocityY * 0.8;
+				block.applyForce(forceX, forceY);
 				bird.velocityX *= 0.5;
 				bird.velocityY *= 0.5;
 			}
 		}
+		// Check block vs block collisions
+		for (var m = 0; m < blocks.length; m++) {
+			var block1 = blocks[m];
+			if (block1.destroyed || block1.isStatic) continue;
+			for (var n = m + 1; n < blocks.length; n++) {
+				var block2 = blocks[n];
+				if (block2.destroyed) continue;
+				if (block1.intersects(block2)) {
+					// Calculate collision response
+					var dx = block2.x - block1.x;
+					var dy = block2.y - block1.y;
+					var distance = Math.sqrt(dx * dx + dy * dy);
+					if (distance > 0) {
+						// Normalize collision vector
+						dx /= distance;
+						dy /= distance;
+						// Separate blocks
+						var overlap = (block1.width + block2.width) / 2 - distance;
+						if (overlap > 0) {
+							block1.x -= dx * overlap * 0.5;
+							block1.y -= dy * overlap * 0.5;
+							block2.x += dx * overlap * 0.5;
+							block2.y += dy * overlap * 0.5;
+						}
+						// Exchange velocities based on mass
+						var totalMass = block1.mass + block2.mass;
+						var v1 = block1.velocityX * dx + block1.velocityY * dy;
+						var v2 = block2.velocityX * dx + block2.velocityY * dy;
+						var newV1 = ((block1.mass - block2.mass) * v1 + 2 * block2.mass * v2) / totalMass;
+						var newV2 = ((block2.mass - block1.mass) * v2 + 2 * block1.mass * v1) / totalMass;
+						block1.velocityX += (newV1 - v1) * dx * 0.8;
+						block1.velocityY += (newV1 - v1) * dy * 0.8;
+						if (!block2.isStatic) {
+							block2.velocityX += (newV2 - v2) * dx * 0.8;
+							block2.velocityY += (newV2 - v2) * dy * 0.8;
+						} else {
+							// Make static block dynamic if hit hard enough
+							var impact = Math.abs(newV1 - v1);
+							if (impact > 2) {
+								block2.applyForce((newV2 - v2) * dx * block2.mass, (newV2 - v2) * dy * block2.mass);
+							}
+						}
+					}
+				}
+			}
+		}
 	}
 }
 // Check win condition
 function checkWinCondition() {