(DEFUN PAINT(X1 Y1 X2 Y2 K)
  (SETQ A(LIST X1 Y1))
  (SETQ B(LIST X2 Y2))
  ;(COMMAND "ОТРЕЗОК"A B)
   (IF (= k  0 )
    (PROGN
           (COMMAND "ОТРЕЗОК"A B) 
    exit
   )
     )  
  ; (DRAGON)
   
  (SETQ S1 (+ X1 X2))
   (SETQ S2 (- Y2 Y1))
    
   (SETQ S11 (/ S1  2 ))
   (SETQ S22 (/ S2  2 ))
   (SETQ TX (+ S11 S22))

  (SETQ Z1 (+ Y1 Y2))
  (SETQ Z2 (- X2 X1))
    
  (SETQ Z11 (/ Z1  2 ))
  (SETQ Z22 (/ Z2  2 ))
  (SETQ TY (- Z11 Z22)) 
  (SETQ KK(- K  1 ))
  

  (PAINT X2 Y2 TX TY KK)
  (PAINT X1 Y1 TX TY KK)
  
)
(DEFUN DRAGON()
 ;(setq X1  30  X2  30  Y1  30  Y2  300  K  0 )
;(Paint X1 Y1 X2 Y2 K)
 (PAINT  100   150   500   150   8 )
)

procedure Dragon(x1,y1,x2,y2,Depth:Longint;canv:TCanvas);
  procedure Paint(x1,y1,x2,y2,k:Longint);
  var tx,ty:Longint;
  begin
   if k= 0  then
    begin
     canv.MoveTo(x1,y1);
     canv.LineTo(x2,y2);
     Exit;                      <===================== !!!
    end;
   tx:=(x1+x2) div  2 +(y2-y1) div  2 ;
   ty:=(y1+y2) div  2 -(x2-x1) div  2 ;
   Paint(x2,y2,tx,ty,k- 1 );
   Paint(x1,y1,tx,ty,k- 1 );
  end;
begin
 Paint(x1,y1,x2,y2,Depth);
end;

(DEFUN PAINT(X1 Y1 X2 Y2 K)
  (SETQ A(LIST X1 Y1))
  (SETQ B(LIST X2 Y2))
 
    (IF (> k  0 )
      (PROGN  
             
            (SETQ S1 (+ X1 X2))
            (SETQ S2 (- Y2 Y1))
            (SETQ S11 (/ S1  2 ))
            (SETQ S22 (/ S2  2 ))
            (SETQ TX (+ S11 S22))
            (SETQ Z1 (+ Y1 Y2))
            (SETQ Z2 (- X2 X1))
            (SETQ Z11 (/ Z1  2 ))
            (SETQ Z22 (/ Z2  2 ))
            (SETQ TY (- Z11 Z22)) 
            (SETQ KK(- K  1 ))
  

            (PAINT X2 Y2 TX TY KK)
            (PAINT X1 Y1 TX TY KK)
       )
       
       (COMMAND "ОТРЕЗОК"A B) 
 
    
   )  

)
(DEFUN DRAGON()
 (PAINT  100   150   500   150   8 )
)