"There are two ways that spreadsheets, as we know them, distort our thinking and lead to bad decisions. The first distortion is the use of point values and simple arithmetic instead of probability distributions and statistical measures. So far as I know, there's no off-the-shelf spreadsheet product—certainly none in common use—that provides for input of numbers as uncertain quantities, even though almost all of our decisions rest on forecasts or on speculations.

There are add-on products that incorporate uncertainty into spreadsheets, and many of them are quite good. Products of this kind that I've favorably reviewed over the years include DecisionTools Pro from Palisade and Crystal Ball Professional and CB Predictor from Decisioneering. It's not too hard to appreciate the difference between products that incorporate uncertainty and those that don't: On the one hand, you've got, "We predict a $1 million profit in the first year"; on the other, "The expected Year 1 profit is $1 million, but there's a 30 percent chance of losses for the first two years." These different statements will lead to quite different discussions."

"The subjects whose tools invited them to imagine alternative scenarios believed they were doing a better job—even though statistical measures of their results showed no improvement in the actual quality of the forecasts. Those subjects did, however, take longer to perform the task. Isn't that the worst nightmare of those who must justify IT's return on investment—spending extra money on a more time-consuming product that yields absolutely no measurable improvement?"

"You're in Flemming's entrance hall. Flemming is traveling in Transylvania right now. There's a blog here, and a mailbox, an SMS terminal, and a phone booth. There's a picture on the wall. There's a WIKI path going off to the right. There are three other visitors standing around looking bewildered. What do you want to do?"

"There are five phone messages for you, 52 new mail messages, 157 new postings in your aggregator. Your family went to the movies. It is 25 degrees. There are four computers there. On the wall you see a calendar and an address book."

Stan Wagon, a mathematician at Macalester College in St. Paul, Minn., has a bicycle with square wheels. It's a weird contraption, but he can ride it perfectly smoothly. His secret is the shape of the road over which the wheels roll.

A square wheel can roll smoothly, keeping the axle moving in a straight line and at a constant velocity, if it travels over evenly spaced bumps of just the right shape. This special shape is called an inverted catenary.

A catenary is the curve describing a rope or chain hanging loosely between two supports. At first glance, it looks like a parabola. In fact, it corresponds to the graph of a function called the hyperbolic cosine. Turning the curve upside down gives you an inverted catenary -- just like each bump of Wagon's road.