During the last three years I have been constructing puzzles for the popular science magazine Illustreret Videnskab, published monthly in Denmark, Finland, France, Norway and Sweden. I believe that for many people it is pure fun to solve mathematical problems, if the task is voluntary, and the problems challenging. Hence supplying a popular magazine with entertaining problems is a great chance to lure mathematical methods of thinking into the minds of the readers, even if they never appreciate this aspect of their behaviour.

I think from my own experience as problem solver and poser, that it is wiser not to over-estimate the reader's knowledge, and not to under-estimate their intelligence. So I hesitate to ask too stupid questions, but not to ask difficult questions which are easily understood.

The puzzles are mainly classical ones from H. E. Dudeney, Sam Loyd etc., but I try to sneak in a little mathematics here and there. E.g. in the problem of the jeep crossing the desert, I added the question, “how big a desert can we cross?” I hoped that some readers would prove the divergence of the harmonic series, and according to letters some did.

To tease computer-freaks, I like to ask questions with very large solutions. A source to such problems is Pell's equation.