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..2575d77d 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 +2,38 @@
 
 public class BoundedBlockingQueue<T> {
 
-
+    T[] items;
     public BoundedBlockingQueue(int capacity) {
-
+        if (capacity <= 0) throw new IllegalArgumentException();
+        items = (T[]) new Object[capacity];
     }
 
-    public void put(T item) throws InterruptedException {
-
+    int size, tail;
+    public synchronized void put(T item) throws InterruptedException {
+        if (item == null) throw new NullPointerException();
+        while (size == items.length) wait();
+        items[tail] = item;
+        if (++tail == items.length) tail = 0;
+        size += 1;
+        notifyAll();
     }
 
-    public T take() throws InterruptedException {
-        return null;
+    int head;
+    public synchronized T take() throws InterruptedException {
+        while (size == 0) wait();
+        T item = items[head];
+        items[head] = null;
+        if (++head == items.length) head = 0;
+        size -= 1;
+        notifyAll();
+        return item;
     }
 
-    public int size() {
-        return 0;
+    public synchronized int size() {
+        return size;
     }
 
     public int capacity() {
-        return 0;
+        return items.length;
     }
 }
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..d65e1b5e 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
@@ -27,9 +27,15 @@ 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 {
+            while (true) {
+                monitor.awaitTurn(id);
+                output.print(message);
+                onTick.run();
+                monitor.tick();
+            }
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
         }
     }
 
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..d6a8e51e 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 +1,24 @@
 package hse.java.lectures.lecture6.tasks.synchronizer;
 
 public class StreamingMonitor {
-    // impl your sync here
-}
+    int[] ids;
+    public StreamingMonitor(int[] ids, int ticksPerWriter) {
+        this.ids = ids;
+        left = ids.length * ticksPerWriter;
+    }
+
+    int left, current;
+    public synchronized void awaitTurn(int id) throws InterruptedException {
+        while (left == 0 || ids[current] != id) wait();
+    }
+
+    public synchronized void awaitDone() throws InterruptedException {
+        while (left > 0) wait();
+    }
+
+    public synchronized void tick() {
+        left -= 1;
+        if (++current == ids.length) current = 0;
+        notifyAll();
+    }
+}
\ 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..abcedbd3 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
@@ -1,5 +1,5 @@
 package hse.java.lectures.lecture6.tasks.synchronizer;
-
+import java.util.Arrays;
 import java.util.List;
 
 public class Synchronizer {
@@ -23,11 +23,24 @@ public Synchronizer(List<StreamWriter> tasks, int ticksPerWriter) {
      */
     public void execute() {
         // add monitor and sync
+        int[] ids = new int[tasks.size()];
+        for (int i = 0; i < tasks.size(); ++i) ids[i] = tasks.get(i).getId();
+
+        Arrays.sort(ids);
+        StreamingMonitor monitor = new StreamingMonitor(ids, ticksPerWriter);
+        for (StreamWriter writer : tasks) writer.attachMonitor(monitor);
+
         for (StreamWriter writer : tasks) {
             Thread worker = new Thread(writer, "stream-writer-" + writer.getId());
             worker.setDaemon(true);
             worker.start();
         }
+
+        try {
+            monitor.awaitDone();
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
     }
 
 }