`<-formed@{isolated|initial|medial|final}' for compatibility mapping
to single character tagged `{isolated|initial|medial|final}'.
            return Q_subscript_of;
          else if (EQ (base, Qcircle))
            return Q_circled_of;
+         else if ( EQ (base, Qisolated)||
+                   EQ (base, Qinitial) ||
+                   EQ (base, Qmedial)  ||
+                   EQ (base, Qfinal) )
+           return
+             Fintern (concat2 (build_string ("<-formed@"),
+                               Fsymbol_name (base)),
+                      Qnil);
          else if (SYMBOLP (base))
            return
              Fintern (concat2 (build_string ("<-"),