10 REM BASIC MANDELBROT SET PLOTTER
20 REM BY N.MCLEAN
30 :
40 GOSUB 390
50 GOSUB 310
60 :
70 REM MAIN LOOP
80 FOR J=20 TO 180 STEP 1
90 FOR I=80 TO 240 STEP 2
100 Q=((I-80)/54)-2:W=((J-20)/54)-1.5
110 GOSUB 200
120 IF B=1 THEN 150
130 E=A AND 3
140 GOSUB 260
150 NEXT I,J
160 POKE 53280,2
170 GET A$:IF A$<>" " THEN 170
180 POKE 53265,27:POKE 53270,200:POKE 53272,21
190 END
199 REM THE MATHS
200 X=0:Y=0:A=0
210 C=(X*X)=(Y*Y):D=2*(X*Y)
220 X=C+Q:Y=D+W:Z=X+Y:A=A+1
230 IF Z<-2 OR Z>2 THEN B=0:RETURN
240 IF A>25 THEN B=1:RETURN
250 GOTO 210
259 REM PLOT POINT
260 CH=INT(I/8):RO=INT(J/8):LN=J AND 7
270 BY=8192+(RO*320)+(CH*8)+LN
280 BI=I AND 7
290 POKE BY,PEEK(BY)OR A(E,BI)
300 RETURN
309 REM SET UP BIT MAP
310 POKE 53265,PEEK(53265)OR 32
320 POKE 53270,PEEK(53270)OR 16
330 POKE 53272,PEEK(53272)OR 8
340 POKE 53280,0:POKE 53281,0
350 FOR X=1024 TO 2023:POKE X,152:NEXT X
360 FOR X=55296 TO 56295:POKE X,7:NEXT X
370 FOR X=8192 TO 16191:POKE X,0:NEXT X
380 RETURN
389 REM SET UP VARIABLES
390 DIM A(3,7)
400 FOR I=0 TO 3
410 FOR J=0 TO 7
420 READ A(I,J)
430 NEXT J,I
440 RETURN
450 DATA 0,0,0,0,0,0,0,0
460 DATA 64,64,16,16,4,4,1,1
470 DATA 128,128,32,32,8,8,2,2
480 DATA 192,192,48,48,12,12,3,3