🚀 go-pugleaf

Though you need Font Editor or some equivalent (ResEdit?) to do it
   ("How can you do it alone??"  -Pete Townsend/the Who),
I figured out a good way to make the Cloverleaf symbol.
Get at the Chicago 12 font (inside the FONT file of SYSTEM in ResEdit)
and click along to character ASCII # 217, which I think is blank.
Make a cloverleaf by observing how they're made in any of the menus.
(You'll have to experiment on the height, etc, a bit.)
Close things up properly so the System doesn't bomb.
Get out Key Caps (either version), and there should be a cloverleaf
on SHIFT OPTION ~ (tilde) in Chicago.  If you're working in Geneva
and hit shift-option ~ you get the bunny rabbit, which you can simply
select and change the font to Chicago.  This makes rough drafts 
rather amusing.  With some experimentation, you will soon note that
the Apple font designer(s) hid little presents for us under the 
shift-option tilde keys in most of the fonts (see one of the early
issues of _Macworld_).
This method is a little tortuous, but it gives you a permanent
Cloverleaf who's keyboard position is easy to remember.
G'luck