#define L1RedPin 4
#define L1GreenPin 3
#define L1BluePin 2

void setup() 
{  
  pinMode(L1RedPin, OUTPUT);
  pinMode(L1GreenPin, OUTPUT);
  pinMode(L1BluePin, OUTPUT);
  
  DisplayColor(0,0,0);


}

void loop() 
{
  Shades();
 // RGB();

}

void Shades()
{
  unsigned int RGBColour[3];

  RGBColour[0] = 255;
  RGBColour[1] = 0;
  RGBColour[2] = 0;  

  for (int decColour = 0; decColour < 3; decColour += 1) 
  {
    int incColour = decColour == 2 ? 0 : decColour + 1;   // ANSWER = (YESNO) ? YES : NO;

    // cross-fade the two colours.
    for(int i = 0; i < 255; i += 1) 
    {
      RGBColour[decColour] -= 1;
      RGBColour[incColour] += 1;
      
      DisplayColor(RGBColour[0], RGBColour[1], RGBColour[2]);
      delay(5);
    }
  }
}

void RGB()
{
  DisplayColor(255,0,0);

   delay(1000);

  DisplayColor(0,255,0);  

  delay(1000);
     
  DisplayColor(0,0,255);  

  delay(1000);
}

void DisplayColor(byte R, byte G, byte B) 
{
  analogWrite(L1RedPin, R);
  analogWrite(L1GreenPin, G);
  analogWrite(L1BluePin, B);
}