My code for motor control using arduino and pulse width modulation

/////////////////////////////////////
// Motor using pulse-width-modulation
// By Ronald A. Richardson
/////////////////////////////////////
int signal = 0;
// Chip enabling inputs
int chipEnable1 = 1;
int chipEnable2 = 2;
// Motor inputs
int input1 = 3; // left side forward
int input4 = 10; // right side forward
int input2 = 5; // left side backwards
int input3 = 9; // right side backwards

void setup()
{
  pinMode(signal, OUTPUT);
  pinMode(chipEnable1, OUTPUT);
  pinMode(chipEnable2, OUTPUT);
  pinMode(input1, OUTPUT);
  pinMode(input4, OUTPUT);
  pinMode(input3, OUTPUT);
  pinMode(input2, OUTPUT);
}

void runSignal()
{
  digitalWrite(signal, HIGH);
  delay(50);
  digitalWrite(signal, HIGH);
  delay(50);
}

void enableMotors()
{
  digitalWrite(chipEnable1, HIGH);
  digitalWrite(chipEnable2, HIGH);
}

void goForward()
{
  analogWrite(input1, 100);
  analogWrite(input4, 100);
}

void goBackward()
{
  analogWrite(input3, 50);
  analogWrite(input2, 50);
}

void loop()
{
  // runSignal(); // Signal notifies that the pins are configured correctly (optional)
  enableMotors(); // Enables both sides of the motor chip
  goForward(); //Spins the motor forward
  // goBackward(); // Spins the motor backward
}