int prd = 1000;
void setup() {
  pinMode(3, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
}

void loop() {
  // red
  digitalWrite(3,1);
  digitalWrite(5,0);
  digitalWrite(6,0);
  delay(prd);
  // orange
  digitalWrite(3,1);
  analogWrite(5, 64);
  digitalWrite(6,0);
  delay(prd);
  // yellow
  digitalWrite(3,1);
  digitalWrite(5,1);
  digitalWrite(6,0);
  delay(prd);
  // green
  digitalWrite(3,0);
  digitalWrite(5,1);
  digitalWrite(6,0);
  delay(prd);
  // light blue
  analogWrite(3, 66);
  analogWrite(5, 170);
  analogWrite(6, 255);
  delay(prd);
  // blue
  digitalWrite(3,0);
  digitalWrite(5,0);
  digitalWrite(6,1);
  delay(prd);
  // purple
  analogWrite(3, 139);
  digitalWrite(5,0);
  digitalWrite(6,1);
  delay(prd);
}