int p = 5;
int r = 1;
int g = 2;
int b = 3;
byte brightness = 255;

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

void loop() {
  brightness = 255;
  // Full Brightness
  analogWrite(p, brightness);
  // Decrement by 75%
  brightness *= .75;

  //Red
  analogWrite(r, 255);
  delay(1000);
  analogWrite(r, (0));
 
  // Yellow
  analogWrite(r, 255);
  analogWrite(b, 51);
  analogWrite(g, 255);

  // Print 75% Bright
  analogWrite(p, brightness);
  // Decrement 50% Bright
  brightness *= .50; 

  delay(1000);
 
  analogWrite(r, 0);
  analogWrite(b, 0);
  analogWrite(g, 0);
 
  // Green
  analogWrite(g, 255);
  // Print 50% Bright
  analogWrite(p, brightness);
  // Decrement 25% Bright
  delay(1000);
  brightness *= 25; 
  analogWrite(g, 0);

  // Blue
  analogWrite(b, 255);
  // Print 25% Bright
  analogWrite(p, brightness);
  // Decrement 0% Bright
  delay(1000);
  brightness *= 0;   
  analogWrite(b, 0);

  // Violet
  analogWrite(r, 255);
  analogWrite(b, 255);
  analogWrite(g, 0);

  // Print 0% Bright
  analogWrite(p, brightness);
 
  delay(1000);

  analogWrite(r, 0);
  analogWrite(b, 0);
  analogWrite(g, 0);
}