Mind Matters News is pleased to offer a new series, “Micro Softies,” from our director, Robert J. Marks, on computers, computing, and the computer industry. – Eds.

Here are some mind stretching questions to tickle the brain. For reasons I will explain, we’ll call them Micro Softies.

To work for Microsoft in its booming days, a prospective employee did not need to have a college degree. Candidates needed only to code skillfully and show that they were clever. I worked at the University of Washington in Seattle near the Microsoft campus during this time. They hired a lot of UW students. Although I did some consulting for nearby Microsoft, I mostly watched their growth from the outside.

Part of the Microsoft hiring process consisted of asking candidates mind-stretching questions to test their cleverness. For example, “Why are manhole covers round?”

Here’s the answer.

Circles, it turns out, are the only manhole cover shape you can’t drop through a hole. A circular manhole cover can’t go through a slightly smaller circular hole. A rectangular manhole cover, on the other hand, can be turned on its side and dropped through the rectangular hole in the ground. This is true for any other reasonably shaped manhole cover. Round manhole covers are the solution.

Here’s another one. You get on a ski lift at the bottom. The ski lift is on a loop. As you go up to the top of the hill, you watch ski lift chairs on your right making their way to the bottom of the hill. If there are 100 chairs on the ski lift, how many chairs pass you on the way to the top?

The unexpected answer is all the remaining 99 chairs you are not sitting on. When you get on the ski lift at the bottom, the chair behind you is on the right. When you get off at the top, the chair in front of you is on your right. All of the 99 chairs have passed.

Motivated by Tom Swifties, let’s call these puzzles Micro Softies. A Tom Swifty is a sentence with an adverb with an adverb that is a pun, an inside joke, in terms of the sentence to which it refers:

• “I love modern art,” said Tom abstractly.
• “I just love camping,” said Tom intently.
• “I’ll take the prisoner downstairs,” said Tom condescendingly.

The term originated from the character Tom Swift in a series of adventure books written in the early 20th century, where the author often avoided using “said” alone and paired it with descriptive adverbs.  

So here’s a Micro Softy for readers to think about:

You go 5 miles south, 10 miles east and 5 miles north and arrive where you started from. Where are you if you are not at the North Pole? Stay tuned for the solution.

Note: The Micro Softies I share here and will share in the future have been gathered over many years, and I’ve since lost track of their exact origins. Some general sources include anecdotes from students interviewed by Microsoft, the column “Mathematical Games” by the late Martin Gardner in Scientific American, the Puzzler section of “Car Talk” on PBS Radio, Marilyn vos Savant’s “Ask Marilyn” column in Parade magazine, and the book Introduction to Evolutionary Informatics.