diff --git a/src/main/java/ru/otus/java/basic/homeworks/homework21/Application.java b/src/main/java/ru/otus/java/basic/homeworks/homework21/Application.java
new file mode 100644
index 0000000..e1b8d65
--- /dev/null
+++ b/src/main/java/ru/otus/java/basic/homeworks/homework21/Application.java
@@ -0,0 +1,65 @@
+package ru.otus.java.basic.homeworks.homework21;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class Application {
+
+    private static Object monitor = new Object();
+    private static int currentLetter = 0;
+    private static char[] letters = {'A', 'B', 'C'};
+
+    public static void main(String[] args) {
+
+        ExecutorService executor = Executors.newFixedThreadPool(3);
+
+        Runnable printA = new Runnable() {
+            @Override
+            public void run() {
+                for (int i = 0; i < 5; i++) {
+                    printLetter(0);
+                }
+            }
+        };
+
+        Runnable printB = new Runnable() {
+            @Override
+            public void run() {
+                for (int i = 0; i < 5; i++) {
+                    printLetter(1);
+                }
+            }
+        };
+
+        Runnable printC = new Runnable() {
+            @Override
+            public void run() {
+                for (int i = 0; i < 5; i++) {
+                    printLetter(2);
+                }
+            }
+        };
+
+        executor.submit(printA);
+        executor.submit(printB);
+        executor.submit(printC);
+
+        executor.shutdown();
+    }
+
+    private static void printLetter(int indexLetter) {
+
+        synchronized (monitor) {
+            while (currentLetter != indexLetter) {
+                try {
+                    monitor.wait();
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            }
+            System.out.print(letters[indexLetter]);
+            currentLetter = (currentLetter + 1) % 3;
+            monitor.notifyAll();
+        }
+    }
+}