diff --git a/ch-11/1-measuring-wheel-speeds/robot.py b/ch-11/1-measuring-wheel-speeds/robot.py
index 0c6a3d0..e529414 100755
--- a/ch-11/1-measuring-wheel-speeds/robot.py
+++ b/ch-11/1-measuring-wheel-speeds/robot.py
@@ -4,7 +4,6 @@ import pio_encoder
 import busio
 import adafruit_vl53l1x
 import math
-import busio
 
 uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
 
diff --git a/ch-11/2-speed-control/robot.py b/ch-11/2-speed-control/robot.py
index b3f060b..af55afc 100755
--- a/ch-11/2-speed-control/robot.py
+++ b/ch-11/2-speed-control/robot.py
@@ -4,7 +4,6 @@ import pio_encoder
 import busio
 import adafruit_vl53l1x
 import math
-import busio
 
 uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
 
diff --git a/ch-11/3-known-distance/robot.py b/ch-11/3-known-distance/robot.py
index fb885b9..67ba9a5 100755
--- a/ch-11/3-known-distance/robot.py
+++ b/ch-11/3-known-distance/robot.py
@@ -4,7 +4,6 @@ import pio_encoder
 import busio
 import adafruit_vl53l1x
 import math
-import busio
 
 uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
 
diff --git a/ch-12/3-always-face-north/robot.py b/ch-12/3-always-face-north/robot.py
index 433d8ec..ea42f6e 100755
--- a/ch-12/3-always-face-north/robot.py
+++ b/ch-12/3-always-face-north/robot.py
@@ -4,7 +4,6 @@ import pio_encoder
 import busio
 import adafruit_vl53l1x
 import math
-import busio
 import adafruit_bno055
 
 uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
diff --git a/ch-12/4-make-known-turn/robot.py b/ch-12/4-make-known-turn/robot.py
index 433d8ec..ea42f6e 100755
--- a/ch-12/4-make-known-turn/robot.py
+++ b/ch-12/4-make-known-turn/robot.py
@@ -4,7 +4,6 @@ import pio_encoder
 import busio
 import adafruit_vl53l1x
 import math
-import busio
 import adafruit_bno055
 
 uart = busio.UART(board.GP12, board.GP13, baudrate=9600)