circle.bas

1000 rem
1100 rem goto 15
1200 BASE=2*4092: POKE 53272,PEEK(53272)OR8
1300 POKE 53265,PEEK(53265)OR32
1400 FOR I=BASE TO BASE+7999:POKE I,0:NEXT
1500 FOR I=1024 TO 2023:POKE I,16:NEXT I
1600 REM GOTO 1160
1700 x=0:  lx=x
1800 y=rnd(1)*75: ly=y
1900 xc=int(rnd(1)*280)+20
2000 yc=int(rnd(1)*150)+30
2100 sum=0
2200 gosub 2400
2300 goto 1700
2400 rem
2500 rem
2600 if x>y then return
2700 if x and 1 then gosub 3500
2800 sum=sum + (x*2)+1
2900 x=x+1
3000 if sum>0 then gosub 3200
3100 goto 2600
3200 sum = sum - (y*2)-1
3300 y=y-1
3400 return
3500 rem
3600 lx=x/2
3700 ly=(y+1)/2
3800 gosub 4000
3900 return
4000 HPSN=lx+xc
4100 VPSN=ly+yc
4200 gosub 6600
4300 HPSN=lx+xc
4400 VPSN=yc-ly
4500 gosub 6600
4600 HPSN=xc-lx
4700 VPSN=ly+yc
4800 gosub 6600
4900 HPSN=xc-lx
5000 VPSN=yc-ly
5100 gosub 6600
5200 HPSN=xc+ly
5300 VPSN=yc+lx
5400 gosub 6600
5500 HPSN=ly+xc
5600 VPSN=yc-lx
5700 gosub 6600
5800 HPSN=xc-ly
5900 VPSN=lx+yc
6000 gosub 6600
6100 HPSN=xc-ly
6200 VPSN=yc-lx
6300 gosub 6600
6400 return
6500 end
6600  xx=INT(HPSN/8)
6700  ROW=INT(VPSN/8)
6800  LINE=VPSN AND 7
6900  BYTE =BASE+ROW*320+8*xx+LINE
7000  BIT=7-(HPSN AND 7)
7100  POKE BYTE,PEEK(BYTE) or (2^BIT)
7200  RETURN