the mandelbrot set diagram in ECMA-55 Minimal Basic

mandelbrot.bas

011 REM MANDELBROT SET
012 REM BY ORIGEDIT
013 REM 22.09.2024
014 REM
015 REM F = Z^2 + C
016 REM
017 REM VARIABLES
018 REM H1, H2 - START AND END X
019 REM V1, V2 - START AND END Y
020 REM S - STEP FOR X1 AND Y1
021 REM X1, Y1 - C
022 REM X2, Y2 - Z
023 REM I - ITERATION COUNTER
024 REM L - LIMIT TO Z
025 REM L1 - LIMIT TO I
026 REM
100 REM SETUP
110 LET H1=-2
120 LET H2=0.6
130 LET V1=-1.2
140 LET V2=1.2
150 LET S=0.035
151 LET L=10
152 LET L1=40
155 REM START
158 LET L2=L^2
160 FOR Y1=V1 TO V2 STEP S
170 FOR X1=H1 TO H2 STEP S
180 GOSUB 300
190 NEXT X1
200 PRINT
210 NEXT Y1
220 STOP
300 REM ITERATE
310 LET X2=0
320 LET Y2=0
330 LET I=0
335 IF I>=L1 THEN 500
340 LET X2= X2^2 - Y2^2 + X1
350 LET Y2= 2*X2*Y2 + Y1
360 LET I=I+1
380 IF X2^2 + Y2^2 <= L2 THEN 335
390 REM OUTSIDE
400 IF I>L1/4 THEN 410
401 PRINT " ";
402 RETURN
410 IF I>L1/2 THEN 420
411 PRINT "-";
412 RETURN
420 PRINT "+";
430 RETURN
500 REM INSIDE
510 PRINT "#";
520 RETURN
530 END