int y,counter,redVal,greenVal,blueVal;
int RGB[2];

void setup() {
  randomSeed(analogRead(A1));
  Serial.begin(9600);
}
 
void loop() {
// y = random(765);
for(int x=255;x>=0;x--){
analogWrite(9, getColor(RGB[0]));
analogWrite(10, getColor(RGB[1]));
analogWrite(11, getColor(RGB[2]));
counter = x * 3;
RGB[0] = counter;
RGB[2] = (counter + 255) % 765; 
RGB[1] = (RGB[2] + 255) % 765;
delay(10);
}
}
int getColor(int x){
  int phase = x / 255;
  int mod = x % 255;
  if (phase == 0){
    return 0;
  }
  if(phase == 1){
    return mod;
  }
  if(phase == 2){
    return 255 - mod;
  }
}