--- a/src/insert_verification/main.c	Sun Mar 20 22:47:53 2016 +0900
+++ b/src/insert_verification/main.c	Sun Mar 20 23:39:31 2016 +0900
@@ -96,28 +96,28 @@
 
 __code duplicateIteratorElem(struct Context* context, struct Allocate* allocate, struct Iterator* iter) {
     // All elements in iterator must be unique.
-    struct IterElem *oldElem = iter->previousDepth->head;
+    struct IterElem *oldElem = iter->previousDepth->head->next;
     struct IterElem *newElem = iter->head;
 
-
     while (newElem->next != NULL) {
         // FIXME: simple implementation O(n^2)
         oldElem = oldElem->next;
         newElem = newElem->next;
     }
 
-    if (oldElem == iter->previousDepth->head) {
+    if (oldElem->val == iter->previousDepth->iteratedValue) {
         newElem->next = iter->head;
-        iter->last    = newElem;
+        iter->last    = iter->head;
         goto duplicateTree_stub(context); // meta
     } else {
         struct IterElem* dup = context->heap;
         allocate->size = sizeof(struct IterElem);
         allocator(context);
 
-        dup->val         = oldElem->next->val;
+        dup->val         = oldElem->val;
         newElem->next    = dup;
-        goto duplicateIteratorElem_stub(context); // meta
+        goto duplicateIteratorElem_stub(context);
+        //goto meta(context, DuplicateIterElem); // meta
     }
 }
 
@@ -137,7 +137,7 @@
 
     showTrace(finishedIter); // FIXME: show trace
 
-    while (finishedIter->head == finishedIter->last) {
+    while (finishedIter->last == finishedIter->head) {
         if (finishedIter->previousDepth == NULL) {
             goto meta(context, ShowTree); // all enumerations finished.
         }