That use of $; is very clever, as it parses correctly and allows you to omit the brackets for the for. Combining this with other modifications yields 122 chars of obfuscated goodness:
print map{$i=$_/20;$/,map{$r=$;=$_/20;$z=$i;$n=$z*$z,$z=2*$r*$z+$i,$r=($m=$r*$r)-$n+$;for a..z;$m<4?$":"+"}-46..13}-20..19
Further savings if you choose 'X' instead of '+':
print map{$i=$_/20;$/,map{$r=$;=$_/20;$z=$i;$n=$z*$z,$z=2*$r*$z+$i,$r=($m=$r*$r)-$n+$;for a..z;$m<4?$":X}-46..13}-20..19
Here is the original C code, just for comparison, at 182 characters: 
void main(){double O,x,o,I,l,i;char _;for(l=-1;l<1;l+=.05,putc
;i<.7;i+=.05,putchar(_?'?':':'),O=i,x=l,o=I=(_=1)--)for(;++_&&
);x=2*O*x+l,O=o-I+i);}

[download]
C allows for shorter variable names, and Perl still comes out ahead. Crazy.

In reply to Re^3: (Golf) Mandelbrot Fractal by tadman
in thread (Golf) Mandelbrot Fractal by {NULE}

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