(define (king x1 y1 x2 y2)
  (if (= y1 7)
      (if (< (abs (- x1 x2)) 2) #t (if (and (>= 5 (- (abs (- x1 x2)) 1)) (< y2 8)) #t #f))
   (if (< (+ y1 1) y2)
      #f
   (if (< y1 (abs (- x1 x2 )))
       #f
    #t))))