function toggleMenu() {
    if (gameState === STATES.PLAYING) {
        pauseGame();
    } else if (gameState === STATES.PAUSED) {
        resumeGame();
    }
}

class Particle {
  constructor(x, y, vx, vy) {
    this.x = x;
    this.y = y;
    this.vx = vx;
    this.vy = vy;
  }
}

class PuzzlePiece {
  onDrag(e) {
    this.pos.x = e.clientX;
    this.pos.y = e.clientY;
    this.checkSnap();
  }
}

function solve(start, end) {
  const queue = [start];
  while(queue.length > 0) {
    let current = queue.shift();
    if(current === end) break;
  }
}

function detectGesture(points) {
  const v1 = getVector(points[0], points[1]);
  const v2 = getVector(points[1], points[2]);
  const angle = calculateAngle(v1, v2);
  return angle > 90 ? 'corner' : 'line';
}