  * Answering visibility polygon query corresponding to any point located exterior to simple polygon amid vertex insertions and deletions to  simple polygon.
<meaning-changed>   * Answering visibility polygon query corresponding to any point located exterior to simple polygon amid vertex insertions and deletions to  simple polygon.
 * An output-sensitive query algorithm to answer the visibility polygon query corresponding to any point located exterior to simple polygon amid vertex insertions and deletions to simple polygon.