pinMode(13, OUTPUT);
l=0;
s=0;
for(;;) {
 if(s==1) {
  if(millis()-p > 200) {
   p=p+200;
   l=!l;
  }
 }
 digitalWrite(13, l);

 if(digitalRead(2)==LOW) {
  t=millis();
  delay(20);
  while(digitalRead(2)==LOW) {
   delay(5);
  }
  if(millis()-t < 500) {
    s=0;
    l=1;
    for(i=0; i<20; i=i+1) {
     if (digitalRead(2)==LOW) {
      s=1;
      delay(20);
      while(digitalRead(2)==LOW) {
       delay(5);
      }
      p=millis();
      break;
     }
     delay(10);
    }
   } else {
    s=0;
    l=0;
   }
 }
}