void setup() {
  // put your setup code here, to run once:
pinMode(0, OUTPUT);
pinMode(1, OUTPUT);
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(10, INPUT);
pinMode(11, INPUT);
pinMode(12, INPUT);
pinMode(13, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
if(digitalRead(10)==1 )led1();
if(digitalRead(11)==1 )led2();
if(digitalRead(12)==1 )led3();
if(digitalRead(13)==1 )led4();
}
void led1(){
digitalWrite(0,1);
delay(500);
digitalWrite(0,0);
delay(500);
}
void led2(){
digitalWrite(1,1);
delay(500);
digitalWrite(1,0);
delay(500);
}
void led3(){
digitalWrite(2,1);
delay(500);
digitalWrite(2,0);
delay(500);
}
void led4(){
digitalWrite(3,1);
delay(500);
digitalWrite(3,0);
delay(500);
}