#include <SoftwareSerial.h>
  
// pin 6 is to receive from the controller and does not need to be connected
// pin 7 needs to be connect to the serial data input of the board
SoftwareSerial pololu(6, 7);
  
int pos = 0;
  
void setup() {
  Serial.begin(9600);
  pololu.begin(9600);
}
  
void loop() {
  Serial.println(pos);
  
  // set position for eight servos simultaneously
  for(int i=0; i<8; i++) {
    setPosition(i, pos);
  }
    
  pos++;
  if(pos >= 255) {
    pos = 0;
  }
  
  delay(10);
}
  
void setPosition(int servo, int pos) {
  pololu.write(0xFF); // write synchronization flag
  pololu.write(servo); // write servo number
  pololu.write(pos); // write position
}

 // ...