<*DEFINE new:=1*>
<*PUSH; new:=2; IF new=2 THEN*>
a
<*END; PUSH; new:=3; IF new=3 THEN*>
b
<*END; POP; IF new=2 THEN*>
c
<*END; POP; IF new=1 THEN*>
d
<*END*>