#include <AccelStepper.h>

#define Ap 12
#define An 13
#define Bp 11
#define Bn 10

void setup()
{
  pinMode(Ap, OUTPUT); pinMode(An, OUTPUT);
  pinMode(Bp, OUTPUT); pinMode(Bn, OUTPUT);
}
int I=0;
void loop()
{
  if(I++ < 100)
  {
  delay(10);
  digitalWrite(Bn, LOW); digitalWrite(Ap, HIGH);
  delay(10);
  digitalWrite(Ap, LOW); digitalWrite(Bp, HIGH);
  delay(10);
  digitalWrite(Bp, LOW); digitalWrite(An, HIGH);
  delay(10);
  digitalWrite(An, LOW); digitalWrite(Bn, HIGH);
  }else while(1);
}