diff --git a/ch-13/1-modelling-space/computer/display_arena_from_robot.py b/ch-13/1-modelling-space/computer/display_arena_from_robot.py
index 8c36ceb..548a4dd 100644
--- a/ch-13/1-modelling-space/computer/display_arena_from_robot.py
+++ b/ch-13/1-modelling-space/computer/display_arena_from_robot.py
@@ -8,14 +8,11 @@ from robot_ble_connection import BleConnection
 
 class RobotDisplay:
     def __init__(self):
-        self.fig, self.ax = plt.subplots()
         self.ble_connection = BleConnection(self.handle_data)
+        self.line = ""
 
         self.arena = None
         self.display_closed = False
-        # handle closed event
-        self.fig.canvas.mpl_connect("close_event", self.handle_close)
-        self.line = ""
 
     def handle_close(self, _):
         self.display_closed = True
@@ -33,13 +30,13 @@ class RobotDisplay:
 
     def update(self, arena):
         self.arena = arena
-        self.ax.clear()
+        plt.gca().clear()
         for line in arena["arena"]:
-            self.ax.plot(
+            plt.gca().plot(
                 [line[0][0], line[1][0]], [line[0][1], line[1][1]], color="black"
             )
         for line in arena["target_zone"]:
-            self.ax.plot(
+            plt.gca().plot(
                 [line[0][0], line[1][0]], [line[0][1], line[1][1]], color="red"
             )
 
@@ -48,9 +45,10 @@ class RobotDisplay:
 
         try:
             await self.ble_connection.connect()
-            request = json.dumps({"type": "arena"}).encode()
+            request = json.dumps({"command": "arena"}).encode()
             print(f"Sending request for arena: {request}")
-            self.ble_connection.send_uart_data(request)
+            await self.ble_connection.send_uart_data(request)
+            plt.gcf().canvas.mpl_connect("close_event", self.handle_close)
 
             while not self.display_closed:
                 plt.pause(0.05)
diff --git a/ch-13/1-modelling-space/computer/find_devices.py b/ch-13/1-modelling-space/computer/find_devices.py
index 829f62c..de4035e 100644
--- a/ch-13/1-modelling-space/computer/find_devices.py
+++ b/ch-13/1-modelling-space/computer/find_devices.py
@@ -8,6 +8,6 @@ async def run():
     print(f"Found {len(devices)} devices")
     print([device.name for device in devices])
     ble_device_info = [device for device in devices if device.name==ble_name][0]
-    print("Found robot {}...".format(ble_device_info.name))
+    print(f"Found robot {ble_device_info.name}...")
 
 asyncio.run(run())
diff --git a/ch-13/1-modelling-space/computer/robot_ble_connection.py b/ch-13/1-modelling-space/computer/robot_ble_connection.py
index 9ea514c..88b25b5 100644
--- a/ch-13/1-modelling-space/computer/robot_ble_connection.py
+++ b/ch-13/1-modelling-space/computer/robot_ble_connection.py
@@ -24,7 +24,7 @@ class BleConnection:
         print(f"Found {len(devices)} devices")
         print([device.name for device in devices])        
         ble_device_info = [device for device in devices if device.name==self.ble_name][0]
-        print("Connecting to {}...".format(ble_device_info.name))
+        print(f"Connecting to {ble_device_info.name}...")
         self.ble_client = bleak.BleakClient(ble_device_info.address)
         await self.ble_client.connect()
         print("Connected to {}".format(ble_device_info.name))
@@ -35,8 +35,5 @@ class BleConnection:
     async def close(self):
         await self.ble_client.disconnect()
                 
-    def send_uart_data(self, data: bytes):
-        if self.ble_client:
-            asyncio.create_task(
-                self.ble_client.write_gatt_char(self.adafruit_tx_uuid, data)
-            )
+    async def send_uart_data(self, data: bytes):
+        await self.ble_client.write_gatt_char(self.adafruit_tx_uuid, data)