byte i=0;    
int del=100; 

void setup() {
	for (i = 6; i<=8 ; i++)	{
		pinMode(i, OUTPUT);
	}
} 

void loop() {
	for (i = 6; i<=8; i++) {
		digitalWrite(i, HIGH);
		delay(del);
		digitalWrite(i, LOW);
	}
	for (i = 7; i>=7; i--) {
		digitalWrite(i, HIGH);
		delay(del);
		digitalWrite(i, LOW);
	}
}




