int led1 = 2;
int led2 = 5;
int led3 = 6;
int mygtukas = 4;

void setup() {
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
pinMode(mygtukas, INPUT); // INPUT - ivedame duomenis
}

void loop() 
{
bool arPaspaustas = digitalRead(mygtukas);
if (arPaspaustas == true) // patikrinam, ar paspaustas mygtukas
{
  // veiksmus, kurie bus ivykdyti
  // jeigu salyga bus teisinga
  digitalWrite(led1, HIGH);
  digitalWrite(led2, LOW);
  digitalWrite(led3, HIGH);
  delay(100);
  digitalWrite(led1, LOW);
  digitalWrite(led2, HIGH);
  digitalWrite(led3, LOW);
  delay(100);
}
else
{
  // jeigu salyga klaidinga
  digitalWrite(led1, HIGH);
  digitalWrite(led2, HIGH);
  digitalWrite(led3, HIGH);
  delay(100);
  digitalWrite(led1, LOW);
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  delay(100);
}
delay(250);
}