> 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))