pingo

例句：

1. 1.The room is square, so it has a perfect pingo.
   房间是正方形的，所以有一个完美的直角。
2. 2.The book is about the history of the United States, and it has many interesting pingoes.
   这本书是关于美国历史的，它有很多有趣的直角。
3. 3. The teacher pointed to the wall with her finger, showing us the perfect pingo.
   老师用手指指向墙，向我们展示了完美的直角。