(define a
  (lambda (x)
    (cond
      ((eq? x 'true) 'true)
      ((eq? x 'false) 'false)
      ((symbol? x) x)
      ((boolean? x) x)
      ((number? x) x)
      ((eq? (a (car (cdr x))) 'and)
         (cond
           ((eq? (a (car x)) 'false) 'false)
           ((eq? (a (car (cdr (cdr x)))) 'false) 'false)
           ((and (eq? (a (car x)) 'true)
                 (eq? (a (car (cdr (cdr x)))) 'true))'true)
         )
      )
      ((eq? (a (car (cdr x))) 'or)
         (cond
           ((eq? (a (car x)) 'true) 'true)
           ((eq? (a (car (cdr (cdr x)))) 'true) 'true)
         )
       )
    )
    ;list((car x)(car (cdr x))(car (cdr (cdr x) )))
  )
)