#define a_in 2
#define a_in 5
#define a_in 6
#define a_m 9

void setup() {
  // Serial.begin(9600);
  // Serial.println("hello Boy");
  pinMode(b_m, OUTPUT);
  pinMode(b_p, OUTPUT);
  pinMode(a_p, OUTPUT);
  pinMode(a_m, OUTPUT);
}

void loop() {
  digitalWrite(a_p, LOW);
  digitalWrite(a_m, HIGH);
  delay(1000);
  digitalWrite(b_p, LOW); // phase - 1
  digitalWrite(b_m, HIGH); // phase - 1
  delay(1000);
  digitalWrite(a_p, HIGH);
  digitalWrite(a_m, LOW);
  delay(1000);
  digitalWrite(b_p, HIGH);
  digitalWrite(b_m, LOW);
  delay(1000);
}