diff --git a/src/heap/vieter_heap_tree.c b/src/heap/vieter_heap_tree.c
index e65fb56..75b38d2 100644
--- a/src/heap/vieter_heap_tree.c
+++ b/src/heap/vieter_heap_tree.c
@@ -4,24 +4,6 @@ vieter_heap_node *vieter_heap_node_init() {
   return calloc(1, sizeof(vieter_heap_node));
 }
 
-vieter_heap_node *vieter_heap_node_merge_same_order(vieter_heap_node *root_a,
-                                                    vieter_heap_node *root_b) {
-  vieter_heap_node *new_root, *new_child;
-
-  if (root_a->key <= root_b->key) {
-    new_root = root_a;
-    new_child = root_b;
-  } else {
-    new_root = root_b;
-    new_child = root_a;
-  }
-
-  new_root->next_largest_order = new_root->largest_order;
-  new_root->largest_order = new_child;
-
-  return new_root;
-}
-
 vieter_heap_tree *vieter_heap_tree_init(vieter_heap_node *root,
                                         vieter_heap_tree *next,
                                         uint64_t order) {
@@ -34,5 +16,93 @@ vieter_heap_tree *vieter_heap_tree_init(vieter_heap_node *root,
   return tree;
 }
 
-vieter_heap_tree *vieter_heap_tree_merge(vieter_heap_tree *tree_a,
-                                         vieter_heap_tree *tree_b) {}
+void vieter_heap_tree_swap(vieter_heap_tree *t1, vieter_heap_tree *t2) {
+    vieter_heap_tree temp = {
+        .order = t1->order,
+        .root = t1->root,
+        .next = t1->next
+    };
+
+    t1->order = t2->order;
+    t1->root = t2->root;
+    t1->next = t2->next;
+
+    t2->order = temp.order;
+    t2->root = temp.root;
+    t2->next = temp.next;
+}
+
+vieter_heap_tree *vieter_heap_tree_merge_same_order(vieter_heap_tree *tree_a,
+                                                    vieter_heap_tree *tree_b) {
+  vieter_heap_tree *new_tree;
+
+  if (tree_a->root->key <= tree_b->root->key) {
+      new_tree = tree_a;
+    tree_a->root->next_largest_order = tree_a->root->largest_order;
+    tree_a->root->largest_order = tree_b->root;
+
+    free(tree_b);
+  } else {
+      new_tree = tree_b;
+    tree_b->root->next_largest_order = tree_b->root->largest_order;
+    tree_b->root->largest_order = tree_a->root;
+
+    free(tree_a);
+  }
+
+  new_tree->order++;
+
+  return new_tree;
+}
+
+vieter_heap_tree *vieter_heap_tree_merge(vieter_heap_tree *tree_a, vieter_heap_tree *tree_b) {
+    vieter_heap_tree *tree, *target;
+
+    if (tree_a->order <= tree_b->order) {
+        target = tree_a;
+        tree = tree_b;
+    } else {
+        target = tree_b;
+        tree = tree_a;
+    }
+
+    vieter_heap_tree *next_tree, *next_target;
+    vieter_heap_tree *previous_target = target;
+
+    while (1) {
+        if (target->order == tree->order) {
+            next_tree = tree->next;
+            next_target = target->next;
+
+            target = vieter_heap_tree_merge_same_order(target, tree);
+
+            // TODO what when this merge produces an order that's already in target
+
+            target->next = next_target;
+            previous_target->next = target;
+
+            tree = next_tree;
+        } else if (target->order > tree->order) {
+            previous_target->next = tree;
+            tree->next = target;
+
+            tree = tree->next;
+        } else {
+            previous_target = target;
+            target = target->next;
+        }
+    }
+
+    if (target->order > tree->order) {
+        vieter_heap_tree_swap(target, tree);
+        
+    } else if (target->order == tree->order) {
+        target->root->next_largest_order = target->root->largest_order;
+        target->root->largest_order = tree->root;
+        target->order++;
+
+        next_tree = tree->next;
+        free(tree);
+        tree = next_tree;
+    }
+}
diff --git a/src/heap/vieter_heap_tree.h b/src/heap/vieter_heap_tree.h
index 18808e1..03b61a4 100644
--- a/src/heap/vieter_heap_tree.h
+++ b/src/heap/vieter_heap_tree.h
@@ -15,8 +15,6 @@ vieter_heap_node *vieter_heap_node_init();
 
 void vieter_heap_node_free(vieter_heap_node *node);
 
-vieter_heap_node *vieter_heap_tree_merge_same_order(vieter_heap_node *root_a, vieter_heap_node *root_b);
-
 typedef struct vieter_heap_tree {
     uint64_t order;
     vieter_heap_node *root;
@@ -27,4 +25,7 @@ vieter_heap_tree *vieter_heap_tree_init(vieter_heap_node *root, vieter_heap_tree
 
 vieter_heap_tree *vieter_heap_tree_merge(vieter_heap_tree *tree_a, vieter_heap_tree *tree_b);
 
+vieter_heap_tree *vieter_heap_tree_merge_same_order(vieter_heap_tree *tree_a,
+                                                    vieter_heap_tree *tree_b);
+
 #endif