Mental Floss 69







The answer to last week’s lateral thinking challenge is. Q: A man lives on the twelfth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator — or if it was raining that day — he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up two flights of stairs to his apartment.

A: The man is a “little person”. He can’t reach the upper elevator buttons, but he can ask people to push them for him, or he can use his umbrella to reach it if it’s raining and he has it on his person.

This week’s lateral thinking challenge is.

Q: Manhole covers for sewer drains are typically circular in shape (the ones that are removable anyway). This shape has an important advantage over a square or rectangular shape. What is it?  

Another lateral challenge will appear next week along with the answer to this one.




Join us for our final Six Thinking Hats training for 2018 in Melbourne on Dec 14. Full details are in the link attached …

Six Thinking Hats training – Melbourne Dec 14, 2018

Have a great weekend!


Share the Post

About the Author

Frank Connolly is the Principal of “Think Quick”, a business that adds value through thinking differently. His work history covers all sectors and includes initiatives that have yielded bottom line benefit in the 10’s of millions of dollars.

Frank has worked across Australia, South East Asia, China, the Middle East and Africa where he has trained and facilitated multiple thinking methods and been acknowledged by Edward de Bono as one of the foremost practitioners of the de Bono thinking methods worldwide.

Frank believes strongly that if we can improve the way we think, the actions that follow also improve.

Comments (1)

  1. Jabr Alnoaimi :

    Hi again!

    1- It is easier to make a circular hole. Using a square or rectangular cover require that one re-shape the hole to fit the shape.

    2- When pressured, a circular hole is better at spreading the pressure on all sides of the circumference. Square or rectangular covers would have the pressure mostly affecting the edge closer to the point of the pressure.

    3- It can be easily flipped open from any point on the circumference.


Your email address will not be published. Required fields are marked *