I figured out how to do this.
Change the step value in line 5 to make the spiral tighter (.2) or wider (.05).
0 'SPIRAL.BAS
5 ST=.1
10 PMODE 4,1:PCLS:SCREEN 1,1
20 FOR R=1 TO 165
30 CIRCLE(128,96),R,1,1,S,S+ST
40 S=S+ST:IF S>1 THEN S=S-1
50 NEXT
999 GOTO 999As an experiment, I switched it to PMODE 0 so there could be eight graphics pages of spirals which could be page flipped to make a cool hypnotic animation.
I miss the fun of BASIC.
How did you do the PMODE0 page flip trick you mentioned? Will that create an animated spiral a la the opening to The Twilight Zone?
Yes! I did t have it lining up yet, but I did a FOR P=1 TO 8 for each screen the started the spiral, then the next loop it would start at a slightly higher ST value. I just need to tweak it so the page flip animation is smoother. I can share the work in progress code if you want to work on it.
10 PCLEAR 8
20 ST=.1
30 FOR P=1 TO 8
40 PMODE 0,P:PCLS:SCREEN 1,1
50 FOR R=1 TO 165
60 CIRCLE(128,96),R+P,1,1,S,S+ST
70 S=S+ST:IF S>1 THEN S=S-1
80 NEXT:NEXT
90 FOR P=1 TO 8:PMODE 0,P:SCREEN 1,1
100 FOR D=1 TO 50:NEXT
110 NEXT:GOTO 90