int r =11;
int g = 10;
int b = 9;

void setup() {
  pinMode(r, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(b, OUTPUT);
}

void up(int led) {
  for (int i = 0; i < 255; i++) {
    analogWrite(led, i);
    delay(10);
  }
}

void dn(int led) {
  for (int i = 255; i > 0; i--) {
    analogWrite(led, i);
    delay(10);
  }
}

void loop() {
  up(r);
  dn(b);
  up(g);
  dn(r);
  up(b);
  dn(g);
}