diff --git a/launch/square_proportional.launch.py b/launch/square_proportional.launch.py
new file mode 100644
index 0000000000000000000000000000000000000000..13c8bf8b54447e49e0423b4b60131f9f34cae271
--- /dev/null
+++ b/launch/square_proportional.launch.py
@@ -0,0 +1,26 @@
+from launch import LaunchDescription
+from launch_ros.actions import Node
+
+
+def generate_launch_description():
+    return LaunchDescription([
+        Node(
+            package='turtlesim',
+            namespace='',
+            executable='turtlesim_node',
+            name='sim'
+        ),
+        Node(
+            package='lesson_05',
+            namespace='',
+            executable='square_proportional',
+            name='square_proportional'
+        ),
+        Node(
+            package='rqt_plot',
+            namespace='',
+            executable='rqt_plot',
+            arguments=['/turtle1/pose/theta', '/turtle1/pose/x', '/turtle1/pose/y'],
+            name='rqt_plot'
+        )
+    ])
diff --git a/lesson_05/square_proportional.py b/lesson_05/square_proportional.py
new file mode 100644
index 0000000000000000000000000000000000000000..f90fea6f1d89e74c61a92d9e1b6091d88fe069b3
--- /dev/null
+++ b/lesson_05/square_proportional.py
@@ -0,0 +1,53 @@
+import rclpy
+from rclpy.node import Node
+
+from geometry_msgs.msg import Twist
+from turtlesim.msg import Pose
+import math
+
+
+def ang_spd(a1, a2):
+    a = a1-a2
+    K_p = 500
+    return K_p*((a+math.pi)%(2*math.pi)-math.pi)
+
+
+class RurMover(Node):
+    def __init__(self):
+        super().__init__('minimal_publisher')
+        self.publisher_twist = self.create_publisher(Twist, 'turtle1/cmd_vel', 10)
+        self.pose_subscriber = self.create_subscription(Pose, 'turtle1/pose', self.pose_callback, 10)
+        self.desired_heading = math.pi / 2
+        self.SIDE_TIME = 5.0
+        self.LINEAR_SPEED = 0.5
+        self.timer = self.create_timer(self.SIDE_TIME, self.pub_timer_callback)
+
+    def pose_callback(self, msg):
+        self.get_logger().info('Current heading: "%f"' % msg.theta)
+        self.get_logger().info('Setpoint: "%f"' % self.desired_heading)
+        msg_pub = Twist()
+        msg_pub.linear.x = self.LINEAR_SPEED
+        ANGULAR_SPEED = ang_spd(self.desired_heading, msg.theta)
+        msg_pub.angular.z = math.radians(ANGULAR_SPEED)
+        if ANGULAR_SPEED > 0:
+            self.get_logger().info('Turn left')
+        else:
+            self.get_logger().info('Turn right')
+        self.publisher_twist.publish(msg_pub)
+
+    def pub_timer_callback(self):
+        self.desired_heading += math.pi / 2
+        self.desired_heading %= 2 * math.pi
+        self.get_logger().info('New angle setpoint: "%f"' % self.desired_heading)
+
+def main(args=None):
+    rclpy.init(args=args)
+
+    mover = RurMover()
+    rclpy.spin(mover)
+
+    mover.destroy_node()
+    rclpy.shutdown()
+
+if __name__ == '__main__':
+    main()