100 CLS

110 PRINT" input pixels size (1 to 64)";: INPUT S

112 CURSOR 0: IF S>64 S=64

114 Z=INT(64/ROOT(S,2)): W=500: IF S=1 W=600

120 FOR D=0 TO 100 STEP S

130 FOR C=110 TO 330 STEP S

140 A=0: B=0: N=0

150 IF N<Z GOTO 300

160 IF N=Z N=15

170 IF N>15 N=N-15

180 GOTO W

220 NEXT C

230 NEXT D

240 INKEY: CURSOR 1: END

300 X=A*A: Y=B*B: P=X+Y

350 IF P<10000 GOTO 370

360 GOTO 160

370 F=(A*A-B*B)/50-220+C

380 B=A*B/25+D

390 A=F: N=N+1

400 GOTO 150

500 RECTANGLE N,N,3*C-340,100-D-S+1,3*C-340+3*S,100-D,1

510 RECTANGLE N,N,3*C-340,100+D-S+1,3*C-340+3*S,100+D,1

520 GOTO 220

600 LINE N,3*C-340,100-D,3*C-338,100-D,1

610 LINE N,3*C-340,100+D,3*C-338,100+D,1

620 GOTO 220