diff --git a/tree.cc b/tree.cc
index c3b3c05..974e297 100644
--- a/tree.cc
+++ b/tree.cc
@@ -5,285 +5,176 @@
 #include <algorithm>
 #include <stdexcept>
 
+// Forward declarations
 class INode;
 class ILink;
 class ILinkMixin;
 
 using NodePtr = std::shared_ptr<INode>;
 using LinkPtr = std::shared_ptr<ILink>;
-using LinkMixinPtr = std::shared_ptr<ILinkMixin>;
 
-class ILink {
-public:
-    virtual ~ILink() = default;
-
-    virtual LinkPtr getParent() const = 0;
-    virtual void setParent(LinkPtr parent) = 0;
-
-    virtual const std::vector<LinkPtr>& getChildren() const = 0;
-    virtual void addChild(LinkPtr child) = 0;
-    virtual void removeChild(LinkPtr child) = 0;
-
-    virtual std::mutex& getLock() = 0;
-    virtual LinkMixinPtr getLinkMixin() const = 0;
-};
+// --- ИНТЕРФЕЙСЫ ---
 
 class ILinkMixin {
 public:
     virtual ~ILinkMixin() = default;
     virtual void linkChild(const NodePtr& child) = 0;
     virtual void unlinkParent() = 0;
-    virtual void unlinkChild(const NodePtr& child) = 0;
-    virtual LinkPtr getLink() const = 0;
-    virtual NodePtr getNode() const = 0;
+    virtual LinkPtr getLink() = 0;
 };
 
-class INode {
+class INode : public ILinkMixin {
 public:
-    virtual ~INode() = default;
-    virtual LinkPtr getLink() const = 0;
-    virtual LinkMixinPtr getLinkMixin() const = 0;
+    ~INode() override = default;
+    virtual const std::string& name() const = 0;
+    // УБРАНО: const. Этот метод используется для получения указателя,
+    // который может участвовать в не-константных операциях.
+    virtual NodePtr getSelf() = 0;
 };
 
-class LeafLink : public ILink {
+class ILink {
 public:
-    explicit LeafLink(NodePtr node) : node_(std::move(node)) {}
-
-    LinkPtr getParent() const override { return parent_; }
-    void setParent(LinkPtr parent) override { parent_ = std::move(parent); }
-
-    const std::vector<LinkPtr>& getChildren() const override {
-        static std::vector<LinkPtr> empty;
-        return empty;
-    }
-
-    void addChild(LinkPtr) override {
-        throw std::logic_error("LeafLink cannot have children");
-    }
-
-    void removeChild(LinkPtr) override {}
-
-    std::mutex& getLock() override { return lock_; }
-    LinkMixinPtr getLinkMixin() const override { return node_->getLinkMixin(); }
-
-private:
-    NodePtr node_;
-    LinkPtr parent_;
-    mutable std::mutex lock_;
+    virtual ~ILink() = default;
+    virtual NodePtr getNode() const = 0;
+    virtual LinkPtr getParent() const = 0;
+    virtual void setParent(const LinkPtr& parent) = 0;
+    virtual const std::vector<LinkPtr>& getChildren() const = 0;
+    virtual void addChild(const LinkPtr& child) = 0;
+    virtual void removeChild(const LinkPtr& child) = 0;
 };
 
-class OneToManyLink : public ILink {
-public:
-    explicit OneToManyLink(NodePtr node) : node_(std::move(node)) {}
-
-    LinkPtr getParent() const override { return parent_; }
-    void setParent(LinkPtr parent) override { parent_ = std::move(parent); }
+// --- РЕАЛИЗАЦИИ LINK ---
 
+class BaseLink : public ILink {
+public:
+    explicit BaseLink(NodePtr node) : owner_node_(node) {}
+    NodePtr getNode() const override { return owner_node_.lock(); }
+    LinkPtr getParent() const override { return parent_.lock(); }
+    void setParent(const LinkPtr& parent) override { parent_ = parent; }
     const std::vector<LinkPtr>& getChildren() const override { return children_; }
-
-    void addChild(LinkPtr child) override { children_.push_back(std::move(child)); }
-
-    void removeChild(LinkPtr child) override {
+    void removeChild(const LinkPtr& child) override {
         children_.erase(std::remove(children_.begin(), children_.end(), child), children_.end());
     }
-
-    std::mutex& getLock() override { return lock_; }
-    LinkMixinPtr getLinkMixin() const override { return node_->getLinkMixin(); }
-
-private:
-    NodePtr node_;
-    LinkPtr parent_;
+protected:
     std::vector<LinkPtr> children_;
-    mutable std::mutex lock_;
+    std::weak_ptr<INode> owner_node_;
+    std::weak_ptr<ILink> parent_;
 };
 
-class OneToOneLink : public ILink {
+class LeafLink : public BaseLink {
 public:
-    explicit OneToOneLink(NodePtr node) : node_(std::move(node)) {}
-
-    LinkPtr getParent() const override { return parent_; }
-    void setParent(LinkPtr parent) override { parent_ = std::move(parent); }
-
-    const std::vector<LinkPtr>& getChildren() const override { return singleChildVec_; }
-
-    void addChild(LinkPtr child) override {
-        if (!singleChildVec_.empty()) {
-            throw std::logic_error("OneToOneLink already has a child");
-        }
-        singleChildVec_.push_back(std::move(child));
-    }
-
-    void removeChild(LinkPtr child) override {
-        if (!singleChildVec_.empty() && singleChildVec_.front() == child) {
-            singleChildVec_.clear();
-        }
-    }
-
-    std::mutex& getLock() override { return lock_; }
-    LinkMixinPtr getLinkMixin() const override { return node_->getLinkMixin(); }
-
-private:
-    NodePtr node_;
-    LinkPtr parent_;
-    std::vector<LinkPtr> singleChildVec_;
-    mutable std::mutex lock_;
+    using BaseLink::BaseLink;
+    void addChild(const LinkPtr&) override { throw std::logic_error("LeafLink cannot have children"); }
 };
 
-// Note: TypedOneToManyLink ensures type-safety on child linkage
-
-template <typename TChild>
-class TypedOneToManyLink : public OneToManyLink {
+class OneToManyLink : public BaseLink {
 public:
-    explicit TypedOneToManyLink(NodePtr node) : OneToManyLink(std::move(node)) {}
-
-    void addChild(LinkPtr child) override {
-        NodePtr n = child->getLinkMixin()->getNode();
-        if (!std::dynamic_pointer_cast<TChild>(n)) {
-            throw std::invalid_argument("TypedOneToManyLink: child is not of expected type");
-        }
-        OneToManyLink::addChild(std::move(child));
-    }
+    using BaseLink::BaseLink;
+    void addChild(const LinkPtr& child) override { children_.push_back(child); }
 };
 
-// Note: BaseLinkMixin is used for direct eager link composition (non-lazy)
+// --- CRTP МИКСИН-РЕАЛИЗАЦИЯ ---
 
-class BaseLinkMixin : public ILinkMixin {
+template <class TFinalNode>
+class LazyLinkMixin : public INode {
 public:
-    explicit BaseLinkMixin(NodePtr self) {
-        link_ = std::make_shared<OneToManyLink>(self);
-    }
-
-    void linkChild(const NodePtr& child) override {
-        LinkPtr childLink = child->getLink();
+    void linkChild(const NodePtr& childNode) override {
+        lazyInit();
+        upgradeLinkIfNeeded();
+        LinkPtr childLink = childNode->getLink();
         childLink->setParent(link_);
         link_->addChild(childLink);
     }
 
     void unlinkParent() override {
-        if (!link_ || !link_->getParent()) return;
-        auto parent = link_->getParent();
-        parent->getLinkMixin()->unlinkChild(getNode());
+        lazyInit();
+        LinkPtr parentLink = link_->getParent();
+        if (!parentLink) return;
+        parentLink->removeChild(this->getLink());
         link_->setParent(nullptr);
+        downgradeLinkIfPossible();
     }
 
-    void unlinkChild(const NodePtr& child) override {
-        LinkPtr childLink = child->getLink();
-        link_->removeChild(childLink);
-        childLink->setParent(nullptr);
+    LinkPtr getLink() override {
+        lazyInit();
+        return link_;
     }
 
-    LinkPtr getLink() const override { return link_; }
-    NodePtr getNode() const override { return self_; }
-
-private:
-    LinkPtr link_;
-    NodePtr self_;
-};
-
-// Note: LazyLinkMixin starts with LeafLink and upgrades dynamically
+protected:
+    // УБРАНО: const. Возвращаем неконстантный указатель.
+    virtual std::shared_ptr<TFinalNode> getShared() = 0;
 
-template <typename TNode>
-class LazyLinkMixin : public ILinkMixin {
-public:
-    explicit LazyLinkMixin(NodePtr self) : self_(self) {
-        link_ = std::make_shared<LeafLink>(self);
-    }
-
-    void linkChild(const NodePtr& child) override {
-        ensureInitialized(child);
-
-        LinkPtr childLink = child->getLink();
-        childLink->setParent(link_);
-        link_->addChild(childLink);
+    // УБРАНО: const. Соответствует базовому классу.
+    NodePtr getSelf() override {
+        return getShared();
     }
 
-    void unlinkParent() override {
-        if (!link_ || !link_->getParent()) return;
-        auto parent = link_->getParent();
-        parent->getLinkMixin()->unlinkChild(getNode());
-        link_->setParent(nullptr);
-
-        if (link_->getChildren().empty()) {
-            link_ = std::make_shared<LeafLink>(getNode());
+private:
+    void lazyInit() {
+        if (!link_) {
+            link_ = std::make_shared<LeafLink>(getSelf());
         }
     }
-
-    void unlinkChild(const NodePtr& child) override {
-        if (!link_) return;
-        LinkPtr childLink = child->getLink();
-        link_->removeChild(childLink);
-        childLink->setParent(nullptr);
-
+    void upgradeLinkIfNeeded() {
+        if (!std::dynamic_pointer_cast<LeafLink>(link_)) return;
+        auto oldParent = link_->getParent();
+        link_ = std::make_shared<OneToManyLink>(getSelf());
+        link_->setParent(oldParent);
+    }
+    void downgradeLinkIfPossible() {
         if (link_->getChildren().empty()) {
-            link_ = std::make_shared<LeafLink>(getNode());
+            auto oldParent = link_->getParent();
+            link_ = std::make_shared<LeafLink>(getSelf());
+            link_->setParent(oldParent);
         }
     }
-
-    LinkPtr getLink() const override { return link_; }
-    NodePtr getNode() const override { return self_; }
-
-private:
-    void ensureInitialized(const NodePtr& child) {
-        if (link_ && !std::dynamic_pointer_cast<LeafLink>(link_)) return;
-
-        LinkPtr oldLink = link_;
-        LinkPtr newLink;
-
-        if (std::dynamic_pointer_cast<TNode>(child)) {
-            newLink = std::make_shared<TypedOneToManyLink<TNode>>(getNode());
-        } else {
-            newLink = std::make_shared<OneToOneLink>(getNode());
-        }
-
-        newLink->setParent(oldLink->getParent());
-        link_ = newLink;
-    }
-
     LinkPtr link_;
-    NodePtr self_;
 };
 
-class SimpleNode : public INode, public std::enable_shared_from_this<SimpleNode> {
+// --- КОНКРЕТНЫЙ УЗЕЛ ---
+
+// УБРАНО: final. Теперь от класса можно наследоваться.
+class SimpleNode : public LazyLinkMixin<SimpleNode>,
+                   public std::enable_shared_from_this<SimpleNode>
+{
 public:
-    static std::shared_ptr<SimpleNode> create(std::string name) {
+    static NodePtr create(std::string name) {
+        // Теперь эта структура может легально наследоваться от SimpleNode
         struct EnableMakeShared : public SimpleNode {
             EnableMakeShared(std::string n) : SimpleNode(std::move(n)) {}
         };
-        auto ptr = std::make_shared<EnableMakeShared>(std::move(name));
-        ptr->initMixin();
-        return ptr;
+        return std::make_shared<EnableMakeShared>(std::move(name));
     }
 
-    const std::string& name() const { return name_; }
-    LinkPtr getLink() const override { return mixin_->getLink(); }
-    LinkMixinPtr getLinkMixin() const override { return mixin_; }
+    const std::string& name() const override { return name_; }
 
-    void linkChild(const std::shared_ptr<SimpleNode>& child) { mixin_->linkChild(child); }
-    void unlinkParent() { mixin_->unlinkParent(); }
+protected:
+    // УБРАНО: const. Теперь возвращается неконстантный shared_ptr, как и ожидается.
+    std::shared_ptr<SimpleNode> getShared() override {
+        return shared_from_this();
+    }
 
 private:
+    friend struct std::enable_shared_from_this<SimpleNode>;
+    friend class LazyLinkMixin<SimpleNode>;
     explicit SimpleNode(std::string name) : name_(std::move(name)) {}
-
-    void initMixin() {
-        mixin_ = std::make_shared<LazyLinkMixin<SimpleNode>>(shared_from_this());
-    }
-
     std::string name_;
-    LinkMixinPtr mixin_;
 };
 
-void printTree(const LinkPtr& link, int indent = 0) {
+// --- УТИЛИТА ДЛЯ ВЫВОДА ---
+
+void printTree(const NodePtr& startNode, int indent = 0) {
+    if (!startNode) return;
     for (int i = 0; i < indent; ++i) std::cout << "  ";
-    auto node = link->getLinkMixin()->getNode();
-    auto simpleNode = std::dynamic_pointer_cast<SimpleNode>(node);
-    if (simpleNode) {
-        std::cout << simpleNode->name() << "\n";
-    }
-    for (const auto& child : link->getChildren()) {
-        printTree(child, indent + 1);
+    std::cout << startNode->name() << "\n";
+    LinkPtr nodeLink = startNode->getLink();
+    for (const auto& childLink : nodeLink->getChildren()) {
+        printTree(childLink->getNode(), indent + 1);
     }
 }
 
+// --- MAIN ---
+
 int main() {
     auto root = SimpleNode::create("Root");
     auto child1 = SimpleNode::create("Child1");
@@ -295,12 +186,12 @@ int main() {
     auto subchild = SimpleNode::create("SubChild");
     child1->linkChild(subchild);
 
-    printTree(root->getLink());
+    printTree(root);
 
-    std::cout << "\nUnlinking Child2...\n";
-    child2->unlinkParent();
+    std::cout << "\nUnlinking Child1...\n";
+    child1->unlinkParent();
 
-    printTree(root->getLink());
+    printTree(root);
 
     return 0;
 }