#define ledcyan  26
#define ledpurple 27
void setup() {
  pinMode(ledcyan, OUTPUT);
  pinMode(ledpurple, OUTPUT);
}

void loop() {
  digitalWrite(ledcyan, HIGH);
  digitalWrite(ledpurple, LOW);
  delay(500);
  digitalWrite(ledcyan, LOW);
  digitalWrite(ledpurple, HIGH);
  delay(500);
}