// Swing LED 
// by BARRAGAN <http://barraganstudio.com> 

int which = 0;                 // variable the keeps which light must be turn on next 
 
void turn_all_off()            // function to turn off all the lights 
{                              // connected to digital pins 0 to 7 
  int i; 
  for(i=0; i<8; i++) 
  { 
    digitalWrite(i, LOW); 
  } 
} 
 
void setup() 
{ 
  int i; 
  for(i=0; i<8; i++)           // initializes pins 0 to 7 as outputs 
  { 
    pinMode(i, OUTPUT);  
  } 
} 
 
void loop() 
{ 
  turn_all_off();              // turns all lights off 
  digitalWrite(which, HIGH);   // sets on the current light on 
  delay(200);                  // waits for 200 milli seconds 
  which = which + 1;           // increment the variable to turn on the next one next time 
  if(which > 7)                // check for the range, if greater then 7 goes back to 0 
  { 
    which = 0; 
  } 
}