The following PostScript code is probably ugly to the eyes of a seasoned postscript-hacker, but it illustrates the above point. I assume you could send it directly to a ps printer.


%!

% To draw a tree of complexity n:
%       * Draw a trunk.       
%       * If n > 0, draw several smaller trees of
%         complexity n-1 on top of the trunk, at angles.


42 srand

/frand { rand 1024 mod 1024 div } bind def
/peturb { frand 0.6 mul 0.4 add mul } bind def

/trunk {
    newpath
    0 0 moveto
    0 150 translate
    0 0 lineto
    stroke
} bind def

/tree {
    dup 0 gt { %if
        1 sub
        trunk
        0.7 dup scale
        [-45 45] { %forall
            gsave
                peturb rotate
                dup tree
            grestore
        } forall
    } if
    pop
} bind def

300 150 translate
6 setlinewidth
6 tree