Imagine that we had a way of sending actors from Broadway to Hollywood that involved putting them in cars and driving them across the country. Some of these cars crashed, killing the poor actors. Sometimes the actors got drunk on the way and shaved their heads or got nasal tattoos, thus becoming too ugly to work in Hollywood, and frequently the actors arrived in a different order than they had set out, because they all took different routes. Now imagine a new service called Hollywood Express, which delivered actors to Hollywood, guaranteeing that they would (a) arrive (b) in order (c) in perfect condition. The magic part is that Hollywood Express doesn't have any method of delivering the actors, other than the unreliable method of putting them in cars and driving them across the country. Hollywood Express works by checking that each actor arrives in perfect condition, and, if he doesn't, calling up the home office and requesting that the actor's identical twin be sent instead. If the actors arrive in the wrong order Hollywood Express rearranges them. If a large UFO on its way to Area 51 crashes on the highway in Nevada, rendering it impassable, all the actors that went that way are rerouted via Arizona and Hollywood Express doesn't even tell the movie directors in California what happened. To them, it just looks like the actors are arriving a little bit more slowly than usual, and they never even hear about the UFO crash. Joel on software: http://www.joelonsoftware.com/articles/LeakyAbstractions.html -- "Mind precedes its objects. They are mind-governed and mind-made. To speak or act with a defiled mind is to draw pain after oneself, like a wheel behind the feet of the animal drawing it." "Mind precedes its objects. They are mind-governed and mind-made. To speak or act with a peaceful mind is to draw happiness after oneself, like an inseparable shadow." "Happy indeed we live who are free from worry among those who are still worried. In the midst of worried men, we live free from worry."