int ledpin1 = 1;
int ledpin2 = 2;
int ledpin3 = 3;

void setup()
{
  pinMode(ledpin1, OUTPUT);
  pinMode(ledpin2, OUTPUT);
  pinMode(ledpin3, OUTPUT);
}
void loop() {
  // put your main code here, to run repeatedly:

digitalWrite(ledpin1, HIGH);
digitalWrite(ledpin2, HIGH);
digitalWrite(ledpin3, HIGH);
delay(500);
digitalWrite(ledpin1, LOW);
digitalWrite(ledpin2, LOW);
digitalWrite(ledpin3, LOW);
delay(500);
}