I like the analogy, walls and webs...too many letter writers miss the difference between black and white and gray areas...it is in the gray areas we see the interrelationships between elements of complex systems, and the complexity is huge! War, the economy, energy have no simple solution...no real black and white. While some would argue the solution is obvious, they then just miss the complexity...they miss the forest for the trees. My only knock on Tom, and i apologize for misspelling his last name in another post, is that even he doesn't really get the intertwining. The ecosystem of a food web vs a food chain is a place to start.