Spiders

I’m sure most of you , by now, have seen enough graphics demonstration programs to make you ill.

Here is one more! This one is a little different, though. Enter the program, but before you RUN it, first edit line 30 to read:

30 FOR j=14 TO 14

The reason for this is that it takes about 10 minutes for the original version to run. With the change, the visual effects aren’t quite as striking but you’ll kind of get the idea of what the long version has in store.

Be prepared for a few suprises!

  10 DIM b(10): DIM c(10): FOR a=1 TO 10
  20 GO SUB 2000
  30 FOR j=2 TO 14
  40 FOR i=0 TO 2*PI STEP PI/10
  50 GO SUB 1000
  60 INK 7-(j/2): PLOT x+j*COS i,y+j*SIN i
  70 NEXT i
  80 NEXT j
  90 NEXT a
 100 FOR a=1 TO 9
 110 FOR n=a TO 9
 120 PLOT b(a),c(a)
 130 LET xx=b(n+1)-b(a): LET yy=c(n+1)-c(a): INK 0
 140 DRAW xx,yy: SOUND 6,15;7,7;8,16;9,16;10,16;12,16;13,0
 150 NEXT n: NEXT a
 160 SOUND 6,6;7,7;8,16;9,16;10,16;12,56;13,8
 170 FOR n=1 TO 250: NEXT n: SOUND 8,0;9,0;10,0: FOR n=1 TO 5000
 180 LET a$=INKEY$: IF a$="" THEN GO TO 180
 190 CLS : RUN
 999 STOP
1000 LET n=INT (i*20.69)-60
1010 BEEP .01,n
1020 BEEP .01,9-n
1030 RETURN
2000 LET x=INT (24*RND)*10+10: LET b(a)=x+2
2010 LET y=INT (16*RND)*10+10: LET c(a)=y
2020 IF a>1 THEN PLOT b(a-1),c(a-1): GO TO 2040
2030 RETURN
2040 LET xx=x-b(a-1): LET yy=y-c(a-1)
2050 DRAW xx,yy
2060 SOUND 6,6;7,7;8,16;9,16;10,16;12,56;13,8
2070 FOR n=1 TO 250: NEXT n: SOUND 8,0;9,0;10,0
2080 PLOT b(a-1),c(a-1): DRAW xx,yy
2090 RETURN