🚀 go-pugleaf

As a LogoWriter user, and not having a WHILE primitive, I would have
tackled Bob's problem with a more obvious recursive procedure:

TO SPIRAL :FIRSTLENGTH :ANGLE
if :FIRSTLENGTH < 175 [stop]
fd :FIRSTLENGTH rt :ANGLE
SPIRAL :FIRSTLENGTH + 2 :ANGLE
END

I really appreciated Brian's discussion of how the interpreter treats
"tail recursion" (I now call this feature "iteration" to avoid confusion
with "real" recursion) and his definition of the procedure WHILE.

I'm not sure I really "approve" of Bob's use of "make" as the way of
updating :FIRSTLENGTH; the recursive call to SPIRAL seems a cleaner way to
accomplish the same thing.

Dave Kressen