RGB LED Colour Fader

//LED pin definitions
const byte redled=9;    // PWM PIN on Uno and Nano
const byte greenled=10; // PWM PIN on Uno and Nano
const byte blueled=11;  // PWM PIN on Uno and Nano

void setup() {
 pinMode(redled,OUTPUT);
 pinMode(greenled,OUTPUT);
 pinMode(blueled,OUTPUT);
// Serial.begin(9600);
}

 void loop() {
  byte potval, counter;
  byte min_potval=5;    // anything between 1-254
  byte max_potval=100;    // anything between 1-254, but max_potvaler then min_potval

  for (counter=1;counter<15;counter++){

   for (potval = min_potval; potval < max_potval; potval++) {     // automatic setting the potvalue
//       Serial.print("counter: "); Serial.print(counter); Serial.println("  ");
//       Serial.print("potval: "); Serial.print(potval); Serial.println("  ");

       switch (counter) {
         case 1: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,min_potval); analogWrite(greenled,min_potval);analogWrite(redled,potval); break;
         case 2: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,min_potval); analogWrite(greenled,min_potval);analogWrite(redled,max_potval-potval); break;
         case 3: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,min_potval); analogWrite(greenled,potval);analogWrite(redled,min_potval); break;
         case 4: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,min_potval); analogWrite(greenled,max_potval-potval);analogWrite(redled,min_potval); break;
         case 5: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,min_potval); analogWrite(greenled,potval);analogWrite(redled,potval); break;
         case 6: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,min_potval); analogWrite(greenled,max_potval-potval);analogWrite(redled,max_potval-potval); break;
         case 7: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,potval); analogWrite(greenled,min_potval);analogWrite(redled,min_potval); break;
         case 8: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,max_potval-potval); analogWrite(greenled,min_potval);analogWrite(redled,min_potval); break;
         case 9: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,potval); analogWrite(greenled,min_potval);analogWrite(redled,potval); break;
         case 10://Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,max_potval-potval); analogWrite(greenled,min_potval);analogWrite(redled,max_potval-potval); break;
         case 11://Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,potval); analogWrite(greenled,potval);analogWrite(redled,min_potval); break;
         case 12://Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,max_potval-potval); analogWrite(greenled,max_potval-potval);analogWrite(redled,min_potval); break;
         case 13: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,potval); analogWrite(greenled,potval);analogWrite(redled,potval); break;
         case 14: //Serial.print("counter: "); Serial.println(counter);
                 analogWrite(blueled,max_potval-potval); analogWrite(greenled,max_potval-potval);analogWrite(redled,max_potval-potval); break;
                 }
 delay (30);  // sets the change speed
            }

      }
 }