const byte minimum = 255;

void rgbLed(const byte R, const byte G, const byte B, const int delay_s = 1)
{
  analogWrite(9,  minimum - R);
  analogWrite(10, minimum - G);
  analogWrite(11, minimum - B);
  delay(delay_s * 1000);
}

void setup()
{
  for(unsigned int i = 9; i <= 11; i++)
    pinMode(i, OUTPUT);
}

void loop()
{
  rgbLed(255, 0, 0);
  rgbLed(0, 255, 0, 1);
  rgbLed(0, 0, 255, 3);
}