English Original
One day, the staff at a zoo held a meeting to address an issue: kangaroos were escaping from their cage. They concluded the cage was too low and decided to raise it from one meter to two meters high.
The next day, the kangaroos were still at large. The staff raised the cage again, this time to three meters.
To their surprise, the kangaroos were free again the following morning. Alarmed, they determined to go to all lengths and raised the cage to ten meters.
Later, a giraffe chatted with some kangaroos. "Do you think they will keep raising your cage?" it asked.
"Hard to say," replied a kangaroo. "If they continue forgetting to fasten the cage door."
中文翻译
一天，动物园的工作人员召开会议，讨论一个棘手的问题：袋鼠从笼子里跑出来了。他们一致认为笼子太矮了，于是决定将笼子的高度从1米加高到2米。
第二天，袋鼠们依然逍遥在外。工作人员再次加高笼子，这次加到了3米。
令他们意外的是，隔天早上袋鼠们又跑出来了。工作人员大为紧张，决定一不做二不休，将笼子加高到了10米。
后来，一只长颈鹿和几只袋鼠闲聊。它问道：“你们觉得他们会继续加高你们的笼子吗？”
“很难说，”一只袋鼠回答，“如果他们继续忘记关门的话。”