Progressions can be linear or geometric. Examples of the former are Moore's Law as applied to transistor packing on integrated chips or the energy output from particle accelerators. Boing Boing points us to a colorful new addition - Crayola's law. I found an unforgettable example of the latter (geometric) in the book Tipping Point which goes something like this: If you have a sufficiently large piece of paper and start to fold it over once and then fold it over again and then again and again... what would be the thickness of the piece of paper after 50 such folds? The thickness of the paper would approximate the distance between the earth and the sun...