int potPin = A0; // potentiometer pin
int motorPin = 9; // motor control pin

void setup() {
  pinMode(potPin, INPUT); // set potentiometer pin as input
  pinMode(motorPin, OUTPUT); // set motor control pin as output
}

void loop() {
  int potValue = analogRead(potPin); // read potentiometer value
  int speed = map(potValue, 0, 1023, 0, 255); // map potentiometer value to PWM range
  analogWrite(motorPin, speed); // set PWM duty cycle for motor speed
}