void setup(){

  int G1 = 6, G2 = 7;
  pinMode(G1, OUTPUT);
  pinMode(G2, OUTPUT);
  
  
}

void loop(){
  int G1 = 6, G2 = 7;
  //10
  digitalWrite(G1, 1);
  digitalWrite(G2, 0);
  delay(500);
  //01
  digitalWrite(G1, 0);
  digitalWrite(G2, 1);
  delay(500);
  //00
  digitalWrite(G1, 0);
  digitalWrite(G2, 0);
  delay(500);
  //11
  digitalWrite(G1, 1);
  digitalWrite(G2, 1);
  delay(500);
}