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