unity 2d object movement in spiral pattern towards the centre of circle

Vector2 movingInSpiral(Vector2 start, float time, float distance) {
  Vector2 direction = Vector2.zero;

  if (time > Mathf.PI) {
    direction.x = Math.Sin(time) * distance;
  } else {
    direction.x = Math.Cos(time) * distance;
  }

  direction.y = Math.Sin(3 * time) * -distance;

  return direction;
}