10 CLS
20 DIM C(1000),D(1000),C1(1000),D1(1000)
30 RANDOMIZE
40 CLS
50 SCREEN 9
60 A=RND:A=INT(640*A)
70 B=RND:B=INT(640*B)
80 FOR I=1 TO 5000
90 CTR=CTR+1
100 C=RND:C(I)=INT(640*C):C1(I)=C(I)
110 D=RND:D(I)=INT(640*D):D1(I)=D1(I)
120 LINE(A,B)-(C(I),D(I))
130 IF I>30 THEN 140 ELSE 190
140 LINE(A,B)-(C1(I-30),D1(I-30)),0
150 IF CTR=30 THEN 160 ELSE 190
160 A=C(I) 'A=RND:A=INT(640*A)
170 B=D(I) 'B=RND:B=INT(640*B)
180 CTR=0
190 NEXT
200 GOTO 60