I spent this weekend participating in the ICFP contest. This year the task was a series of problems of increasing difficulty in which we had to steer a satellite orbiting the Earth in order to accomplish various objectives. Like the task last year, it depended heavily on physics, mathematics, your knowledge of a particular domain and the stability of your numerical calculations, not to mention the need for the occasional compensating manoeuvre. It was fairly tedious and I didn't quite enjoy it as much as I did the tasks from some of the previous years.
Are you better off if your investment first gains 10% of its value and then loses 10% or if it first loses 10% in value and then gains 10%? Many of us immediately tend to think that we're back to where we started in both the cases, but a little thought would reveal that we have lost money in both the cases.