How to modify code of " "Adafruit 16-channel PWM & Servo driver Servo test"

Hi, my project need servonum #0~7 rotate same direction, same time; meanwhile, servonum #8~15 roate oppsite direction, same time.
How to modify the example code of "Adafruit 16-channel PWM & Servo driver Servo test", Thank!!!

/***************************************************
This is an example for our Adafruit 16-channel PWM & Servo driver
Servo test - this will drive 16 servos, one after the other

Pick one up today in the adafruit shop!
------> Adafruit 16-Channel 12-bit PWM/Servo Driver - I2C interface [PCA9685] : ID 815 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits

These displays use I2C to communicate, 2 pins are required to
interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4

Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!

Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/

#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>

// called this way, it uses the default address 0x40
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
// you can also call it with a different address you want
//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);

// Depending on your servo make, the pulse width min and max may vary, you
// want these to be as small/large as possible without hitting the hard stop
// for max range. You'll have to tweak them as necessary to match the servos you
// have!
#define SERVOMIN 150 // this is the 'minimum' pulse length count (out of 4096)
#define SERVOMAX 600 // this is the 'maximum' pulse length count (out of 4096)

// our servo # counter
uint8_t servonum = 0;

void setup() {
Serial.begin(9600);
Serial.println("16 channel Servo test!");

pwm.begin();

pwm.setPWMFreq(60); // Analog servos run at ~60 Hz updates
}

// you can use this function if you'd like to set the pulse length in seconds
// e.g. setServoPulse(0, 0.001) is a ~1 millisecond pulse width. its not precise!
void setServoPulse(uint8_t n, double pulse) {
double pulselength;

pulselength = 1000000; // 1,000,000 us per second
pulselength /= 60; // 60 Hz
Serial.print(pulselength); Serial.println(" us per period");
pulselength /= 4096; // 12 bits of resolution
Serial.print(pulselength); Serial.println(" us per bit");
pulse *= 1000;
pulse /= pulselength;
Serial.println(pulse);
pwm.setPWM(n, 0, pulse);
}

void loop() {
// Drive each servo one at a time
Serial.println(servonum);
for (uint16_t pulselen = SERVOMIN; pulselen < SERVOMAX; pulselen++) {
pwm.setPWM(servonum, 0, pulselen);
}
delay(500);
for (uint16_t pulselen = SERVOMAX; pulselen > SERVOMIN; pulselen--) {
pwm.setPWM(servonum, 0, pulselen);
}
delay(500);

servonum ++;
if (servonum > 15) servonum = 0;
}

void loop() {
  // Sweep the servos
  for (uint16_t pulselen = 0; pulselen < SERVOMAX-SERVOMIN; pulselen++) {
    for (int servonum = 0; servonum<8; servonum++)
        pwm.setPWM(servonum, 0, SERVOMIN+pulselen);
    for (int servonum = 8; servonum<16; servonum++)
        pwm.setPWM(servonum, 0, SERVOMAX-pulselen);
 }
  delay(500);
}

Hi, my project need servonum #0~7 rotate same direction, same time; meanwhile, servonum #8~15 roate oppsite direction, same time.

You probably only have to use two control lines for the servos, one for each 0-7 and one for 8-15. the below is a way to set servos for opposite rotation.

myservo1.write(n);
myservo2.write(180-n); //turns opposite side servo in desired direction