What was once a Microsoft innovation has now become a trend, and we’re not talking operating systems here. The newest Microsoft spawn is the “brain teaser” job interview question — such as: Why are soda cans tapered? How do they make M&Ms? And the oft-quoted, Why are manhole covers round?

William Poundstone, who studied these questions for his book How Would You Move Mount Fuji?, found that they’ve spread from Microsoft to Wall Street to Silicon Valley and points in between. Why? They allow interviewers to observe problem-solving in action. Technology companies especially like to use the questions because the pace of change in technology forces jobs to change quickly.

So how do you cope with a brain teaser? First, try not to appear rattled. Take a breath and then a minute to think. Ask questions if you need more information. And take comfort in the fact that not even the interviewer knows the “right” answer.