int m=13;
int n=12;
int o=8;

void setup(){
pinMode(13, OUTPUT);
pinMode(12, OUTPUT);
pinMode(8, OUTPUT);}

void loop(){
digitalWrite(m, HIGH);
digitalWrite(n, LOW);
digitalWrite(o, LOW);
delay(1000);

digitalWrite(m, LOW);
digitalWrite(n, HIGH);
digitalWrite(o, LOW);
delay(1000);

digitalWrite(m, LOW);
digitalWrite(n, LOW);
digitalWrite(o, HIGH);
delay(1000);
}