# assuming
my $h = 5;   # or whatever
my $f = 0.3; # ditto
tree($h,$f);

sub tree {
# counting from here
print$"x--$_[0],"*\n";$.=3;for(reverse 0..$_[0]-1){print$"x$_,map({rand()<$f?substr'0@*+',rand(4),1:$_}split//,'='x$.),"\n";$.+=2}
# to here give 129 chars
}