diff --git a/b2/SUBST b/b2/SUBST
index 92d3253..3d7dc28 100644
--- a/b2/SUBST
+++ b/b2/SUBST
@@ -2,6 +2,16 @@ FN=DNP { ignore }
 
 FN=X(*) { $=$1 }
 
+/* iteration demo */
+FOO=abcde
+BAR=x	/* BAR= wouldn't be syntactically correct. We need a non-empty value */
+FOO=(*)(?) {
+	BAR=$BAR$2
+	FOO=$1
+	again FOO
+}
+BAR=x(*) { $=$1 }	/* remove the "x" */
+
 REF=R[0-9]* {
 	T=R
 	VAL=(#R) { R=$1 }
diff --git a/b2/subex.c b/b2/subex.c
index 76971db..bb4005f 100644
--- a/b2/subex.c
+++ b/b2/subex.c
@@ -183,7 +183,8 @@ static int do_match(const char **var, const regex_t *re,
 
 static const struct subst *recurse_sub(const struct subst *sub,
     const struct param *in, const char *matched_var, const char *matched_val,
-    const regmatch_t *match, const char *units, struct param **out)
+    const regmatch_t *match, const char *units, struct param **out,
+    enum subst_type *cause)
 {
 	const struct subst *jump;
 	regmatch_t m_tmp[NMATCH];
@@ -200,9 +201,13 @@ static const struct subst *recurse_sub(const struct subst *sub,
 			    in, *out, &val, m_tmp))
 				break;
 			jump = recurse_sub(sub->u.match.block, in,
-			    var, val, m_tmp, sub->u.match.units, out);
-			if (jump && jump != sub)
-				return jump;
+			    var, val, m_tmp, sub->u.match.units, out, cause);
+			if (jump) {
+				if (jump != sub)
+					return jump;
+				if (*cause == st_again)
+					continue;
+			}
 			break;
 		case st_assign:
 			tmp = compose(sub->u.assign.pat, in, *out, matched_val,
@@ -217,11 +222,9 @@ static const struct subst *recurse_sub(const struct subst *sub,
 		case st_ignore:
 			return &jump_ignore;
 		case st_break:
-			sub = sub->u.jump->next;
-			continue;
 		case st_again:
-			sub = sub->u.jump->u.match.block;
-			continue;
+			*cause = sub->type;
+			return sub->u.jump;
 		default:
 			abort();
 		}
@@ -236,6 +239,7 @@ int substitute(const struct subst *sub, const struct param *in,
 {
 	int i;
 	char tmp[4];
+	enum subst_type cause = 0;
 
 	if (!fn) {
 		fn = unique("FN");
@@ -245,6 +249,6 @@ int substitute(const struct subst *sub, const struct param *in,
 		}
 	}
 	*out = NULL;
-	return recurse_sub(sub, in, NULL, NULL, NULL, NULL, out)
+	return recurse_sub(sub, in, NULL, NULL, NULL, NULL, out, &cause)
 	    != &jump_ignore;
 }