diff --git a/commander/src/main/java/hse/java/commander/MainController.java b/commander/src/main/java/hse/java/commander/MainController.java
index 5de3b66d..fa18335e 100644
--- a/commander/src/main/java/hse/java/commander/MainController.java
+++ b/commander/src/main/java/hse/java/commander/MainController.java
@@ -1,45 +1,133 @@
 package hse.java.commander;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+
 import javafx.fxml.FXML;
 import javafx.scene.control.Button;
 import javafx.scene.control.ListView;
-
-import java.nio.file.Path;
+import javafx.scene.input.MouseEvent;
 
 public class MainController {
 
-    @FXML
-    public ListView<String> left;
+    private enum FileOperation {
+        COPY, MOVE, DELETE
+    }
 
-    @FXML
-    public ListView<String> right;
+    @FXML public ListView<String> left;
+    @FXML public ListView<String> right;
 
-    @FXML
-    public Button move;
+    @FXML public Button move;
+    @FXML public Button copy;
+    @FXML public Button delete;
 
     private Path leftDir;
     private Path rightDir;
 
+    private boolean isLeftActive = true;
+
     // for testing
     public void setInitialDirs(Path leftStart, Path rightStart) {
         this.leftDir = leftStart;
         this.rightDir = rightStart;
+        refreshPanels();
+    }
+
+    private void updateList(Path dir, ListView<String> dir_list) {
+        dir_list.getItems().clear();
+        dir_list.getItems().add("...");
+
+        if (dir != null) {
+            try (java.nio.file.DirectoryStream<Path> dirStream = java.nio.file.Files.newDirectoryStream(dir)) {
+                for (Path path : dirStream) {
+                    dir_list.getItems().add(path.getFileName().toString());
+                }
+            } catch (java.io.IOException e) {
+                System.err.println(e.getMessage());
+            }
+        }
     }
 
     public void initialize() {
-        move.setOnMouseClicked(event -> {
+        if (leftDir == null) leftDir = Path.of(System.getProperty("user.home"));
+        if (rightDir == null) rightDir = Path.of(System.getProperty("user.home"));
+
+        refreshPanels();
+
+        left.setOnMouseClicked(event -> handlePanelClick(event, left, true));
+        right.setOnMouseClicked(event -> handlePanelClick(event, right, false));
+
+        if (copy != null) copy.setOnAction(e -> executeOperation(FileOperation.COPY));
+        if (move != null) move.setOnAction(e -> executeOperation(FileOperation.MOVE));
+        if (delete != null) delete.setOnAction(e -> executeOperation(FileOperation.DELETE));
+    }
+
+    private void handlePanelClick(MouseEvent event, ListView<String> list, boolean isLeft) {
+        isLeftActive = isLeft;
+
+        if (isLeft) {
+            right.getSelectionModel().clearSelection();
+        } else {
+            left.getSelectionModel().clearSelection();
+        }
 
-        });
-        System.out.println(System.getProperty("user.home"));
-        left.getItems().add("Kek");
+        if (event.getClickCount() == 2) {
+            String selected = list.getSelectionModel().getSelectedItem();
+            if (selected == null) return;
 
-        left.setOnMouseClicked(event -> {
-            if (event.getClickCount() == 2) {
-                int index = left.getSelectionModel().getSelectedIndex();
-                if (index >= 0) {
-                    left.getItems().set(index, "clicked");
+            Path currentDir = isLeft ? leftDir : rightDir;
+            Path newDir;
+
+            if (selected.equals("...")) {
+                newDir = currentDir.getParent();
+            } else {
+                newDir = currentDir.resolve(selected);
+            }
+
+            if (newDir != null && Files.isDirectory(newDir)) {
+                if (isLeft) leftDir = newDir; else rightDir = newDir;
+                refreshPanels();
+            }
+        }
+    }
+
+    private void executeOperation(FileOperation op) {
+        ListView<String> activeList = isLeftActive ? left : right;
+        Path sourceDir = isLeftActive ? leftDir : rightDir;
+        Path targetDir = isLeftActive ? rightDir : leftDir;
+
+        String selected = activeList.getSelectionModel().getSelectedItem();
+
+        if (selected == null || selected.equals("...")) return;
+
+        Path sourcePath = sourceDir.resolve(selected);
+
+        try {
+            switch (op) {
+                case COPY -> {
+                    Path targetPath = targetDir.resolve(selected);
+                    Files.copy(sourcePath, targetPath, StandardCopyOption.REPLACE_EXISTING);
+                }
+                case MOVE -> {
+                    Path targetPath = targetDir.resolve(selected);
+                    Files.move(sourcePath, targetPath, StandardCopyOption.REPLACE_EXISTING);
+                }
+                case DELETE -> {
+                    Files.delete(sourcePath);
                 }
             }
-        });
+        } catch (IOException e) {
+            System.err.println(e.getMessage());
+        }
+
+        refreshPanels();
+    }
+
+    private void refreshPanels() {
+        updateList(leftDir, left);
+        updateList(rightDir, right);
     }
 }
+
diff --git a/src/main/java/hse/java/lectures/lecture6/tasks/queue/BoundedBlockingQueue.java b/src/main/java/hse/java/lectures/lecture6/tasks/queue/BoundedBlockingQueue.java
index 816f3ee6..ff9cffd3 100644
--- a/src/main/java/hse/java/lectures/lecture6/tasks/queue/BoundedBlockingQueue.java
+++ b/src/main/java/hse/java/lectures/lecture6/tasks/queue/BoundedBlockingQueue.java
@@ -2,24 +2,77 @@
 
 public class BoundedBlockingQueue<T> {
 
+    private class Node<T> {
+        T value;
+        Node<T> next;
+
+        Node(T value_) {
+            value = value_;
+            next = null;
+        }
+    }
+
+    private final int capacity_;
+    private int size_;
+    private Node<T> first = null;
+    private Node<T> last = null;
 
     public BoundedBlockingQueue(int capacity) {
+        if (capacity <= 0) {
+            throw new IllegalArgumentException();
+        }
+        capacity_ = capacity;
+    }
 
+    public synchronized void put(T item) throws InterruptedException {
+        if (item == null) {
+            throw new NullPointerException("");
+        }
+        Node<T> node = new Node<>(item);
+        while (isFull()) {
+            this.wait();
+        }
+        if (first == null) {
+            first = node;
+            last = node;
+        } else {
+            last.next = node;
+            last = node;
+        }
+        size_++;
+        this.notifyAll();
     }
 
-    public void put(T item) throws InterruptedException {
+    public synchronized boolean isFull() {
+        return size_ == capacity_;
+    }
 
+    public synchronized boolean isEmpty() {
+        return size_ == 0;
     }
 
-    public T take() throws InterruptedException {
-        return null;
+    public synchronized  T take() throws InterruptedException {
+        while (isEmpty()) {
+            this.wait();
+        }
+    
+        T ret = first.value;
+
+        first = first.next;
+        if (first == null) {
+            last = null;
+        }
+        size_--;
+        this.notifyAll();
+
+        return ret;
     }
 
-    public int size() {
-        return 0;
+    public synchronized int size() {
+        return size_;
     }
 
-    public int capacity() {
-        return 0;
+    public synchronized int capacity() {
+        return capacity_;
     }
 }
diff --git a/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamWriter.java b/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamWriter.java
index fedb5e66..a4747d95 100644
--- a/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamWriter.java
+++ b/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamWriter.java
@@ -1,9 +1,9 @@
 package hse.java.lectures.lecture6.tasks.synchronizer;
 
-import lombok.Getter;
-
 import java.io.PrintStream;
 
+import lombok.Getter;
+
 public class StreamWriter implements Runnable {
 
     private final String message;
@@ -26,11 +26,20 @@ public void attachMonitor(StreamingMonitor monitor) {
 
     @Override
     public void run() {
-        // Writer threads are intentionally infinite for the task contract.
         while (true) {
-            output.print(message);
-            onTick.run();
+            try {
+                if (!monitor.waitMyTurn(id)) {
+                    break; 
+                }
+                
+                output.print(message);
+                onTick.run();
+                
+                monitor.finishMyTurn();
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                break;
+            }
         }
     }
-
-}
+}
\ No newline at end of file
diff --git a/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamingMonitor.java b/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamingMonitor.java
index 68e8f279..50c8de19 100644
--- a/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamingMonitor.java
+++ b/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/StreamingMonitor.java
@@ -1,5 +1,32 @@
 package hse.java.lectures.lecture6.tasks.synchronizer;
 
 public class StreamingMonitor {
-    // impl your sync here
-}
+    private final int[] orderedIds;
+    private final int maxTotalTicks;
+    private int currentTurnIndex = 0;
+    private int currentTotalTicks = 0;
+
+    public StreamingMonitor(int[] orderedIds, int ticksPerWriter) {
+        this.orderedIds = orderedIds;
+        this.maxTotalTicks = orderedIds.length * ticksPerWriter;
+    }
+
+    public synchronized boolean waitMyTurn(int id) throws InterruptedException {
+        while (currentTotalTicks < maxTotalTicks && orderedIds[currentTurnIndex] != id) {
+            wait();
+        }
+        return currentTotalTicks < maxTotalTicks;
+    }
+
+    public synchronized void finishMyTurn() {
+        currentTotalTicks++;
+        currentTurnIndex = (currentTurnIndex + 1) % orderedIds.length;
+        notifyAll();
+    }
+
+    public synchronized void awaitCompletion() throws InterruptedException {
+        while (currentTotalTicks < maxTotalTicks) {
+            wait();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/Synchronizer.java b/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/Synchronizer.java
index 3cb8aded..687f1860 100644
--- a/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/Synchronizer.java
+++ b/src/main/java/hse/java/lectures/lecture6/tasks/synchronizer/Synchronizer.java
@@ -17,17 +17,25 @@ public Synchronizer(List<StreamWriter> tasks, int ticksPerWriter) {
         this.ticksPerWriter = ticksPerWriter;
     }
 
-    /**
-     * Starts infinite writer threads and waits until each writer prints exactly ticksPerWriter ticks
-     * in strict ascending id order.
-     */
     public void execute() {
-        // add monitor and sync
+        int[] orderedIds = tasks.stream()
+                .mapToInt(StreamWriter::getId)
+                .sorted()
+                .toArray();
+
+        StreamingMonitor monitor = new StreamingMonitor(orderedIds, ticksPerWriter);
+
         for (StreamWriter writer : tasks) {
+            writer.attachMonitor(monitor);
             Thread worker = new Thread(writer, "stream-writer-" + writer.getId());
             worker.setDaemon(true);
             worker.start();
         }
-    }
 
-}
+        try {
+            monitor.awaitCompletion();
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+}
\ No newline at end of file