diff --git a/app/build.gradle b/app/build.gradle
index c5cf1b8..009dc4d 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -3,9 +3,9 @@ plugins {
     id 'org.jetbrains.kotlin.android'
 }
 
-kotlin {
-    jvmToolchain(17)
-}
+//kotlin {
+//    jvmToolchain(17)
+//}
 
 android {
     compileSdk 34
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 9604b34..c2e9051 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -21,6 +21,19 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+
+        <activity
+            android:name=".ActivityA"
+            android:exported="false"
+            android:launchMode="standard"
+            />
+
+        <activity
+            android:name=".ActivityB"
+            android:exported="false"
+            android:launchMode="standard"
+            />
+
     </application>
 
 </manifest>
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/ActivityA.kt b/app/src/main/java/otus/gpb/homework/fragments/ActivityA.kt
new file mode 100644
index 0000000..1caf9be
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/ActivityA.kt
@@ -0,0 +1,26 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import android.widget.Button
+import androidx.appcompat.app.AppCompatActivity
+
+class ActivityA : AppCompatActivity() {
+
+    private lateinit var fragmentA: FragmentA
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_a)
+
+        if (savedInstanceState == null) {
+
+            fragmentA = FragmentA()
+
+            supportFragmentManager.beginTransaction()
+                .replace(R.id.fragmentA_container, fragmentA)
+                .addToBackStack(null)
+                .commit()
+        }
+
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/ActivityB.kt b/app/src/main/java/otus/gpb/homework/fragments/ActivityB.kt
new file mode 100644
index 0000000..34e8503
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/ActivityB.kt
@@ -0,0 +1,35 @@
+package otus.gpb.homework.fragments
+
+import android.content.res.Configuration
+import android.os.Bundle
+import android.view.View
+import android.widget.FrameLayout
+import androidx.appcompat.app.AppCompatActivity
+import java.util.Objects
+
+class ActivityB : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_b)
+
+        // ландшафтный режим - отобразить оба фрагмента одновременно
+        if (isLandscape()) {
+            findViewById<FrameLayout>(R.id.frameLayout_bb).visibility = View.VISIBLE
+            supportFragmentManager.beginTransaction()
+                .replace(R.id.frameLayout_ba, FragmentBA())
+                .replace(R.id.frameLayout_bb, FragmentBB())
+                .commit()
+        }
+        else {
+            // портретный режим режим - отобразить только один фрагмент
+            findViewById<FrameLayout>(R.id.frameLayout_bb).visibility = View.GONE
+            supportFragmentManager.beginTransaction()
+                .replace(R.id.frameLayout_ba, FragmentBA())
+                .commit()
+        }
+    }
+
+    private fun isLandscape() =
+        Objects.equals(Configuration.ORIENTATION_LANDSCAPE, resources.configuration.orientation)
+}
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentA.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentA.kt
new file mode 100644
index 0000000..376741f
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/FragmentA.kt
@@ -0,0 +1,49 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.activity.OnBackPressedCallback
+import androidx.fragment.app.Fragment
+
+
+class FragmentA : Fragment() {
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?,
+    ): View? {
+        val view = inflater.inflate(R.layout.fragment_a, container, false)
+        val openFragmentAAButton = view.findViewById<Button>(R.id.buttonOpenFragmentAA)
+
+        requireActivity().onBackPressedDispatcher.addCallback(
+            viewLifecycleOwner,
+            object : OnBackPressedCallback(true) {
+                override fun handleOnBackPressed() {
+                    if (childFragmentManager.backStackEntryCount > 0) {
+                        childFragmentManager.popBackStack()
+                    } else {
+                        requireActivity().finish()
+                    }
+                }
+            }
+        )
+
+        openFragmentAAButton.setOnClickListener {
+            val fragmentAa = FragmentAA()
+            val args = Bundle()
+            args.putInt("color", ColorGenerator.generateColor())
+            fragmentAa.arguments = args
+
+            childFragmentManager.beginTransaction()
+                .add(R.id.frame_layout_fragment_a, fragmentAa)
+                .addToBackStack(null)
+                .commit()
+        }
+
+        return view
+    }
+}
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentAA.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentAA.kt
new file mode 100644
index 0000000..aa6bfcc
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/FragmentAA.kt
@@ -0,0 +1,36 @@
+package otus.gpb.homework.fragments
+
+import android.graphics.Color
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.fragment.app.Fragment
+
+class FragmentAA : Fragment() {
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?,
+    ): View? {
+        val view = inflater.inflate(R.layout.fragment_aa, container, false)
+
+        arguments?.getInt("color")?.let { view.setBackgroundColor(it) }
+
+        view.findViewById<Button>(R.id.button_openFragmentAB).setOnClickListener {
+            val fragmentAb = FragmentAB()
+            val args = Bundle()
+            args.putInt("color", ColorGenerator.generateColor())
+            fragmentAb.arguments = args
+
+            parentFragmentManager.beginTransaction()
+                .replace(R.id.frame_layout_fragment_a, fragmentAb)
+                .addToBackStack(null)
+                .commit()
+        }
+
+        return view
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentAB.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentAB.kt
new file mode 100644
index 0000000..3e00600
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/FragmentAB.kt
@@ -0,0 +1,22 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+
+class FragmentAB : Fragment() {
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?,
+    ): View? {
+        val view = inflater.inflate(R.layout.fragment_ab, container, false)
+
+        arguments?.getInt("color")?.let { view.setBackgroundColor(it) }
+
+        return view
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentBA.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentBA.kt
new file mode 100644
index 0000000..ea621b3
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/FragmentBA.kt
@@ -0,0 +1,58 @@
+package otus.gpb.homework.fragments
+
+import android.content.res.Configuration
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.fragment.app.Fragment
+import java.util.Objects
+
+private val KEY_COLOR = "key_color"
+
+class FragmentBA: Fragment() {
+
+    private var color: Int = 0
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?, ): View? {
+        val view = inflater.inflate(R.layout.fragment_ba, container, false)
+
+        parentFragmentManager.setFragmentResultListener(KEY_COLOR, this) { _, bundle ->
+            color = bundle.getInt(KEY_COLOR)
+            view.setBackgroundColor(color)
+        }
+
+        val openFragBB = view.findViewById<Button>(R.id.buttonOpenFragmentBB)
+
+        // в ландшафтном режиме кнопки "Открыть BB" не должно быть
+        openFragBB.visibility = when (isLandscape()) {
+            true -> View.GONE
+            false -> View.VISIBLE
+        }
+
+        // в портретном режиме при нажатии на кнопку вместо BA открыть BB
+        openFragBB.setOnClickListener {
+            parentFragmentManager.beginTransaction()
+                .replace(R.id.frameLayout_ba, FragmentBB())
+                .addToBackStack(null)
+                .commit()
+        }
+
+
+
+        return view
+    }
+
+    private fun isLandscape(): Boolean =
+        Objects.equals(Configuration.ORIENTATION_LANDSCAPE, resources.configuration.orientation)
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        outState.putInt(KEY_COLOR, color)
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentBB.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentBB.kt
new file mode 100644
index 0000000..485ff81
--- /dev/null
+++ b/app/src/main/java/otus/gpb/homework/fragments/FragmentBB.kt
@@ -0,0 +1,34 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.fragment.app.Fragment
+
+class FragmentBB: Fragment() {
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?,
+    ): View? {
+        val view = inflater.inflate(R.layout.fragment_bb, container, false)
+
+        val fragmentBA = FragmentBA()
+        view.findViewById<Button>(R.id.buttonSendColor)
+            .setOnClickListener {
+                parentFragmentManager.beginTransaction()
+                    .replace(R.id.frameLayout_ba, fragmentBA).apply {
+                        val args = Bundle()
+                        args.putInt("key_color", ColorGenerator.generateColor())
+                        fragmentBA.arguments = args
+                        parentFragmentManager.setFragmentResult("key_color", args)
+                    }
+                    .commit()
+            }
+
+        return view
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/otus/gpb/homework/fragments/MainActivity.kt b/app/src/main/java/otus/gpb/homework/fragments/MainActivity.kt
index 5e89c44..e53fca2 100644
--- a/app/src/main/java/otus/gpb/homework/fragments/MainActivity.kt
+++ b/app/src/main/java/otus/gpb/homework/fragments/MainActivity.kt
@@ -1,6 +1,8 @@
 package otus.gpb.homework.fragments
 
+import android.content.Intent
 import android.os.Bundle
+import android.widget.Button
 import androidx.appcompat.app.AppCompatActivity
 
 class MainActivity : AppCompatActivity() {
@@ -8,5 +10,13 @@ class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
+
+        findViewById<Button>(R.id.openActivityA).setOnClickListener {
+            startActivity(Intent(this, ActivityA::class.java))
+        }
+
+        findViewById<Button>(R.id.openActivityB).setOnClickListener {
+            startActivity(Intent(this, ActivityB::class.java))
+        }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_a.xml b/app/src/main/res/layout/activity_a.xml
new file mode 100644
index 0000000..d29895e
--- /dev/null
+++ b/app/src/main/res/layout/activity_a.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".ActivityA">
+    
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/fragmentA_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/material_dynamic_neutral70"
+        />
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_b.xml b/app/src/main/res/layout/activity_b.xml
new file mode 100644
index 0000000..2e482fa
--- /dev/null
+++ b/app/src/main/res/layout/activity_b.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".ActivityB">
+
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/frameLayout_ba"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        />
+
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/frameLayout_bb"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        />
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 17eab17..49a6c12 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -15,4 +15,25 @@
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <Button
+        android:id="@+id/openActivityA"
+        android:layout_width="200dp"
+        android:layout_height="48dp"
+        app:layout_constraintBottom_toTopOf="@+id/openActivityB"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        android:text="Open Activity A"
+        />
+
+    <Button
+        android:id="@+id/openActivityB"
+        android:layout_width="200dp"
+        android:layout_height="48dp"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        android:text="Open Activity B"
+        />
+
 </androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_a.xml b/app/src/main/res/layout/fragment_a.xml
new file mode 100644
index 0000000..8436d61
--- /dev/null
+++ b/app/src/main/res/layout/fragment_a.xml
@@ -0,0 +1,28 @@
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:padding="16dp"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="This is fragment A"
+        android:textAlignment="center"
+        />
+
+    <Button
+        android:id="@+id/buttonOpenFragmentAA"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_centerHorizontal="true"
+        android:layout_gravity="center_horizontal"
+        android:text="Open fragment AA"
+        android:textAllCaps="false"/>
+
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/frame_layout_fragment_a"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_below="@id/buttonOpenFragmentAA" />
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_aa.xml b/app/src/main/res/layout/fragment_aa.xml
new file mode 100644
index 0000000..d30796a
--- /dev/null
+++ b/app/src/main/res/layout/fragment_aa.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/textView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:text="This is fragment AA"
+        />
+
+    <Button
+        android:id="@+id/button_openFragmentAB"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:text="Open fragment AB"
+        android:textAllCaps="false"/>
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_ab.xml b/app/src/main/res/layout/fragment_ab.xml
new file mode 100644
index 0000000..65efa94
--- /dev/null
+++ b/app/src/main/res/layout/fragment_ab.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <TextView
+        android:id="@+id/textView"
+        android:layout_height="50dp"
+        android:layout_width="match_parent"
+        android:text="this is fragment AB"
+        android:textAlignment="center"
+        />
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_ba.xml b/app/src/main/res/layout/fragment_ba.xml
new file mode 100644
index 0000000..ab394a6
--- /dev/null
+++ b/app/src/main/res/layout/fragment_ba.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="This is fragment BA"
+        android:layout_gravity="center_horizontal"
+        />
+
+    <Button
+        android:id="@+id/buttonOpenFragmentBB"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:text="Open Fragment BB"
+        android:textAllCaps="true"/>
+
+</FrameLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_bb.xml b/app/src/main/res/layout/fragment_bb.xml
new file mode 100644
index 0000000..c7ad4e6
--- /dev/null
+++ b/app/src/main/res/layout/fragment_bb.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="This is fragment BB"
+        android:layout_gravity="center_horizontal"
+        />
+
+    <Button
+        android:id="@+id/buttonSendColor"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:text="Send color"
+        android:textAllCaps="true"/>
+
+</FrameLayout>
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index bd20018..6818023 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
-    id 'com.android.application' version '8.7.2' apply false
-    id 'com.android.library' version '8.7.2' apply false
+    id 'com.android.application' version '8.7.3' apply false
+    id 'com.android.library' version '8.7.3' apply false
     id 'org.jetbrains.kotlin.android' version '2.0.21' apply false
 }