#define red OCR0A
#define green OCR0B



red = 253;                                                //

green = 254;                                            // starting point sets led to be red



    while (1)                                                                   // while loop sets the colour by increamenting OCR0A and OCR0B
  {

        for (int i=0    ; i<252; i++){red--; _delay_ms(delay); } red=1;


        for (int i=0    ; i<252; i++){green--; _delay_ms(delay); } green=2;


        for (int i=0    ; i<252; i++){red++; green++; _delay_ms(delay); } red=253; green=254;
  }

ISR(TIMER0_COMPA_vect)
{
    PORTA &= ~(1<<greenLED);                                //green on
    PORTD |= (1<<redLED);                                      //red off
}
ISR(TIMER0_COMPB_vect)
{
    PORTD &= ~(1<<blueLED);                                  //blue on
    PORTA |= (1<<greenLED);                                   //green off
}
ISR(TIMER0_OVF_vect)
{
    PORTD &= ~(1<<redLED);                                  //red on
    PORTD |= (1<<blueLED);                                    //blue off
}