10 CLS 3
20 COLOR,,,,2
30 X=320:Y=170
40 PI=3.1415927#:Z=10
50 N(0)=1:N(1)=2:N(2)=4:N(3)=17
60 N(4)=18:N(5)=20:N(6)=33:N(7)=34
70 FOR I=0 TO 7
80  SCREEN 2,0,I,N(I) : CLS 2
90 A(I)=PI/180*45*(I+1)
100 C(I)=COS(A(I))
110 S(I)=SIN(A(I))
120 LINE(410-Z*S(I),90+Z*C(I))-(190-Z*S(I),90+Z*C(I))
130 LINE(190-Z*S(I),90+Z*C(I))-(190-Z*S(I),310+Z*C(I))
140 LINE(190-Z*S(I),310+Z*C(I))-(410-Z*S(I),310+Z*C(I))
150 LINE(410-Z*S(I),310+Z*C(I))-(410-Z*S(I),90+Z*C(I))
160 FOR K=0 TO (I+1)*45
170 A1=-K*PI/180:A2=-(K+1)*PI/180
180 LINE(190+10*SIN(A1),310+10*COS(A1))-(190+10*SIN(A2),310+10*COS(A2))
190 NEXT K
200 FOR J=1 TO 990
210 A1=-J*PI/180:A2=-(J+1)*PI/180:B=PI/3:S=I*PI/4:V=-PI/180:RB=5
220 XM11=RB*COS(A1)+RB*A1*SIN(A1)-Z*S(I):XM12=RB*COS(A2)+RB*A2*SIN(A2)-Z*S(I)
230 YM11=RB*SIN(A1)-RB*A1*COS(A1)+Z*C(I):YM12=RB*SIN(A2)-RB*A2*COS(A2)+Z*C(I)
240 XM21=RB*COS(A1)+RB*(A1-B)*SIN(A1)-Z*S(I):XM22=RB*COS(A2)+RB*(A2-B)*SIN(A2)-Z*S(I)
250 YM21=RB*SIN(A1)-RB*(A1-B)*COS(A1)+Z*C(I):YM22=RB*SIN(A2)-RB*(A2-B)*COS(A2)+Z*C(I)
260 XF31=RB*COS(A1+P)+RB*A1*SIN(A1+P):XF32=RB*COS(A2+P)+RB*A2*SIN(A2+P)
270 YF31=RB*SIN(A1+P)-RB*A1*COS(A1+P):YF32=RB*SIN(A2+P)-RB*A2*COS(A2+P)
280 XF41=RB*COS(A1+P)+RB*(A1-B)*SIN(A1+P):XF42=RB*COS(A2+P)+RB*(A2-B)*SIN(A2+P)
290 YF41=RB*SIN(A1+P)-RB*(A1-B)*COS(A1+P):YF42=RB*SIN(A2+P)-RB*(A2-B)*COS(A2+P)
300 LINE(XM11+300,YM11+200)-(XM12+300,YM12+200)
310 LINE(XM21+300,YM21+200)-(XM22+300,YM22+200)
320 LINE(-XF31+300,-YF31+200)-(-XF32+300,-YF32+200)
330 LINE(-XF41+300,-YF41+200)-(-XF42+300,-YF42+200)
340 CIRCLE(300-Z*S(I),200+Z*C(I)),Z/2
350 CIRCLE(300,200),Z/2
360 LINE(-(RB*COS(V+P)+RB*V*SIN(V+P))+300,-(RB*SIN(V+P)-RB*V*COS(V+P))+200)-(-(RB*COS(V+P)+RB*(V-B)*SIN(V+P))+300,-(RB*SIN(V+P)-RB*(V-B)*COS(V+P))+200)
370 IF J-INT(J/4)*4=0 THEN LINE(XM11+300,YM11+200)-(XM21+300,YM21+200)
380 IF J=990 THEN LINE(XM12+300,YM12+200)-(XM22+300,YM22+200):LINE(-XF32+300,-YF32+200)-(-XF42+300,-YF42+200)
390 NEXT J
400 NEXT I
410 FOR I=0 TO 7
420 SCREEN 2,,,N(I)
430 FOR T=1 TO 5999!:NEXT T
440 NEXT I
450 GOTO 410
460 END