I checked out the link to the original site http://rosettacode.org/wiki/Mandelbrot_set and they had a DEC BASIC-PLUS/PDP-11 version. So I fired up my Clone and converted the program to Microsoft MBASIC.

I have to say it doesn't look as nice as the BBC version, but hey it works!

- Code: Select all
`10 X1=59:Y1=21`

20 I1=-1:I2=1:R1=-2:R2=1

30 S1=(R2-R1)/X1:S2=(I2-I1)/Y1

40 FOR Y=0 TO Y1

50 I3=I1+S2*Y

60 FOR X=0 TO X1

70 R3=R1+S1*X:Z1=R3:Z2=I3

80 FOR N=0 TO 30

90 A=Z1*Z1:B=Z2*Z2

100 IF A+B>4 THEN GOTO 130

110 Z2=2*Z1*Z2+I3:Z1=A-B+R3

120 NEXT N

130 IF N=31 THEN PRINT " "; ELSE PRINT CHR$(62-N);

140 NEXT X

150 PRINT

160 NEXT Y

170 END