int j=8; //LEDS start at pin 8

void setup() { //setup() is only gone through once
  for(int i=0; i<4; i++)
  //You have to tell the arduinoboard if pins are INPUT or OUTPUT
  pinMode(j+i, OUTPUT); //make LED-pins outputs.
    //Look at image over board. Top row is for programming pins.
    //The pins can also take input
    //I suppose for example the thermometer has to take input,
    //that is you take input FROM the thermometer and read it somehow.
}

// the loop function runs over and over again forever
void loop() {

  digitalWrite(j, HIGH);  //Turn pin on, this case LED
  delay(100);             //delay 0.1seconds
  digitalWrite(j, LOW);   //Turn it off
  delay(100);             //delay 0.1seconds
  j++;                    //Target next pin.
  if( j>11) //if J will become 12, that is we were on the last LED-pin
    j=8;    //start over on pin 8, that is, the RED LED-pin.
}