10 RANDOMIZE
20 SCREEN 9
30 A=RND:A=INT(640*A)
40 B=RND:B=INT(640*B)
50 FOR I=1 TO 30
60 C=RND:C=INT(640*C)
70 D=RND:D=INT(640*D)
80 LINE(A,B)-(C,D)
90 LINE(A,B)-(C,D),0
100 NEXT
110 GOTO 30