100 ' G48 T.WAKAMATSU
110 DIM A(11),B(11),C(11),D(6145),E(6145)
120 FOR I=1 TO 11
130   A(I)=0:B(I)=0:C(I)=1
140 NEXT I
150 N=1:J=0:CLS
160 V=190:W=335:X=190:Y=330
170 D(0)=V:E(0)=W:D(1)=X:E(1)=Y
180 LINE (V,W)-(X,Y),PSET,%1
190 P=1:GOSUB *LINE:P=-1:GOSUB *LINE
200 '-------------------------------
210 J=J+1:IF J=11 THEN 310
220 A(J)=A(J)+1
230 IF A(J)=2 THEN A(J)=0:GOTO 210
240 K=B(J)+C(J)
250 IF K=0 OR K=2 THEN C(J)=-C(J)
260 P=-C(J):B(J)=1:GOSUB *LINE
270 P=1:GOSUB *LINE:P=-1:GOSUB *LINE
280 J=1:GOTO 220
290 '-------------------------------
310 C1=3:C2=2
320 FOR J=1 TO N
330   IF J=N/2+1   THEN C1=4:C2=5
340   IF J=N/4*3+1 THEN C1=7:C2=6
350   LINE (  D(J-1),  E(J-1))-(  D(J),  E(J)),PSET,%C1
360   LINE (D(N-J+1),E(N-J+1))-(D(N-J),E(N-J)),PSET,%C2
370 NEXT J
390 FOR J=1 TO N/2
400   IF J=N/2+1   THEN C1=4:C2=5
410   IF J=N/4*3+1 THEN C1=7:C2=1
420   LINE (  D(J-1),  E(J-1))-(  D(J),  E(J)),PSET,0
430   LINE (D(N-J+1),E(N-J+1))-(D(N-J),E(N-J)),PSET,0
440 NEXT J
450 GOTO 560
460 '-------------------------------
470 *LINE
480    S=(Y-W)*P+X:T=(V-X)*P+Y
490    V=X:W=Y:X=S:Y=T:N=N+1:D(N)=X:E(N)=Y
500    LINE -(X,Y),PSET,%1
510  RETURN
520 '-------------------------------
560 CLS