#include <Stepper.h>

const int stepsPerRevolution = 200; 
Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);
Stepper myStepper2(stepsPerRevolution, 4, 3, 5, 6);

void setup() {
  myStepper.setSpeed(60);  // rpm
  Serial.begin(9600);
}

void loop() {
  myStepper.step(stepsPerRevolution * 2);
  myStepper2.step(stepsPerRevolution * 2);
  delay(500);
  
  myStepper.step(-stepsPerRevolution);
  delay(500);
}