#define Off 0
#define On 1
int LedPin = 13;
int switchPin = 9;
int toggle = On;
unsigned long interval= 300;

void setup() {
  // put your setup code here, to run once:
pinMode(LedPin, OUTPUT);
pinMode(switchPin, INPUT_PULLUP);

}

void loop() {
  // put your main code here, to run repeatedly:
  if (digitalRead(switchPin) == LOW || toggle == Off){
    toggle = Off;
  while (digitalRead(switchPin) == LOW){
    led_flush();
  }
  led_flush();
  }
  if (digitalRead(switchPin)== LOW && toggle == Off){
    toggle = On;
    while (digitalRead(switchPin)== LOW){
      led_flush();

    }
  }
  }
 
void led_flush (){
  digitalWrite(LedPin, HIGH);
  delay(interval);
  digitalWrite(LedPin, LOW);
  delay(interval);
}