const int motorPin1 = 9;
const int motorPin2 = 10;

void setup() {
    pinMode(motorPin1, OUTPUT);
    pinMode(motorPin2, OUTPUT);
}

void loop() {
    digitalWrite(motorPin1, HIGH);
    digitalWrite(motorPin2, LOW);
    delay(1000);
    digitalWrite(motorPin1, LOW);
    digitalWrite(motorPin2, HIGH);
    delay(1000);
}