cs5/10-tidbit-2-revenge-of-the-bit/11.rkt

#lang racket

(let ([x 4]
      [y 5])
  (+ x y))

(let* ([x 4]
       [y (sqr x)])
  (- y 3))

(let ([x 4])
  (let ([y (sqr x)])
    (- y 3)))

#;(let ([x 4]
      [y (sqr x)]) ;; unbound x
  (- y 3))