#define LED_01 12
#define LED_02 13
#define DIP 7

/*
  no if statement
  1 delay function
*/
void setup() {
  // put your setup code here, to run once:
  pinMode(LED_01, OUTPUT);
  pinMode(LED_02, OUTPUT);
  pinMode(DIP, INPUT);
}

byte pair = 1; 

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(LED_01,  digitalRead(DIP) && pair);
  digitalWrite(LED_02, !digitalRead(DIP) && pair);
  delay(250);

  pair = !pair;
}