> Yes, that is a confusing way to write and read code, rather than a linear flow, like flattening the tree by extracting functions into separate definitions. I

> Yes, that is a confusing way to write and read code, rather than a linear flow, like flattening the tree by extracting functions into separate definitions. I don't understand. It's harder to flatten the tree: you have to unflatten it in your mind afterwards to understand what's happening. It's easier to just visualize, say, this lisp function as a tree directly. (defun good-enough-p (guess x) (format t "~% Guess =~7,4f Guess^2 = ~7,4f Error= ~7,4f" guess (* guess guess) (abs (- (* guess guess) x))) (< (abs (- (* guess guess) x)) .001))