--- a/src/insert_verification/akashaLLRBContext.c	Sun Mar 20 19:05:43 2016 +0900
+++ b/src/insert_verification/akashaLLRBContext.c	Sun Mar 20 22:47:53 2016 +0900
@@ -119,7 +119,7 @@
     allocate->size = sizeof(struct IterElem);
     allocator(context);
 
-    ie->val    = 0;
+    ie->val    = 1;
     ie->next   = NULL;
     iter->tree = NULL;
     iter->head = ie;
@@ -131,7 +131,7 @@
 }
 
 __code initIteratorElem(struct Context* context, struct Allocate* allocate, struct IterElem* prev) {
-    if (prev->val+1 == LIMIT_OF_VERIFICATION_SIZE) { goto initFinishIterator(context, prev); }
+    if (prev->val == LIMIT_OF_VERIFICATION_SIZE) { goto initFinishIterator(context, prev); }
 
     struct IterElem* ie = context->heap;
     allocate->size = sizeof(struct IterElem);

--- a/src/insert_verification/include/akashaLLRBContext.h	Sun Mar 20 19:05:43 2016 +0900
+++ b/src/insert_verification/include/akashaLLRBContext.h	Sun Mar 20 22:47:53 2016 +0900
@@ -2,7 +2,7 @@
 #include "stack.h"
 
 #define ALLOCATE_SIZE 1000
-#define LIMIT_OF_VERIFICATION_SIZE 4
+#define LIMIT_OF_VERIFICATION_SIZE 2
 
 enum Code {
     ShowTree,
@@ -117,5 +117,6 @@
         struct Iterator* previousDepth;
         struct IterElem* head;
         struct IterElem* last;
+        unsigned int iteratedValue;
     } iterator;
 };

--- a/src/insert_verification/main.c	Sun Mar 20 19:05:43 2016 +0900
+++ b/src/insert_verification/main.c	Sun Mar 20 22:47:53 2016 +0900
@@ -4,6 +4,7 @@
 #include "akashaCS.h"
 
 extern void allocator(struct Context* context);
+void showTrace(struct Iterator* iter); //FIXME
 
 void printTree(struct Node* node, int n) {
     if (node != 0) {
@@ -52,13 +53,12 @@
 }
 
 __code putAndGoToNextDepth(struct Context* context, struct Iterator* iter, struct Tree* tree, struct Node* node) {
-    node->key   = iter->head->val;
-    node->value = iter->head->val;
-    iter->head  = iter->head->next;
+    node->key           = iter->head->val;
+    node->value         = iter->head->val;
+    iter->head          = iter->head->next;
+    iter->iteratedValue = node->value;
 
-    printf("%d\n", node->value);
-
-    if (iter->head == iter->last) {
+    if (iter->head == iter->head->next) {
         context->next = GoToPreviousDepth;
     } else {
         context->next = DuplicateIterator;
@@ -96,34 +96,29 @@
 
 __code duplicateIteratorElem(struct Context* context, struct Allocate* allocate, struct Iterator* iter) {
     // All elements in iterator must be unique.
-
-    if ((iter->last != NULL) && (iter->last == iter->previousDepth->last)) {
-        goto meta(context, ShowTree); /* copy tree */
-    }
-    struct IterElem* dup = context->heap;
-    allocate->size = sizeof(struct IterElem);
-    allocator(context);
-
     struct IterElem *oldElem = iter->previousDepth->head;
     struct IterElem *newElem = iter->head;
 
 
-    while ((newElem->next != NULL) && (oldElem->val == newElem->val)) {
+    while (newElem->next != NULL) {
         // FIXME: simple implementation O(n^2)
         oldElem = oldElem->next;
         newElem = newElem->next;
     }
 
-    dup->val         = oldElem->next->val;
-    newElem->next    = dup;
+    if (oldElem == iter->previousDepth->head) {
+        newElem->next = iter->head;
+        iter->last    = newElem;
+        goto duplicateTree_stub(context); // meta
+    } else {
+        struct IterElem* dup = context->heap;
+        allocate->size = sizeof(struct IterElem);
+        allocator(context);
 
-    if (oldElem->next == iter->previousDepth->last) {
-        dup->next  = iter->head;
-        iter->last = dup;
-        goto duplicateTree_stub(context); // meta
+        dup->val         = oldElem->next->val;
+        newElem->next    = dup;
+        goto duplicateIteratorElem_stub(context); // meta
     }
-
-    goto duplicateIteratorElem_stub(context); // meta
 }
 
 __code duplicateTree_stub(struct Context* context) {
@@ -140,17 +135,31 @@
 __code goToPreviousDepth(struct Context* context) {
     struct Iterator* finishedIter = &context->data[Iter]->iterator;
 
-    if (finishedIter->previousDepth == NULL) {
-        goto meta(context, ShowTree); // all enumerations finished.
-    }
+    showTrace(finishedIter); // FIXME: show trace
 
-    context->data[Iter] = (union Data*)finishedIter->previousDepth;
-    context->data[Tree] = (union Data*)finishedIter->previousDepth->tree;
-    // TODO: cleanup memory
+    while (finishedIter->head == finishedIter->last) {
+        if (finishedIter->previousDepth == NULL) {
+            goto meta(context, ShowTree); // all enumerations finished.
+        }
+
+        finishedIter = finishedIter->previousDepth;
+        // TODO: cleanup memory
+    }
+    context->data[Iter] = (union Data*)finishedIter;
+    context->data[Tree] = (union Data*)finishedIter->tree;
 
     goto meta(context, PutAndGoToNextDepth);
 }
 
+void showTrace(struct Iterator* iter) {
+    printf("show trace(reversed):");
+
+    for (; iter != NULL; iter = iter->previousDepth) {
+        printf("%u ", iter->iteratedValue);
+    }
+    printf("\n");
+}
+
 int main(int argc, char const* argv[]) {
     goto startCode(PutAndGoToNextDepth);
 }