Traffic Light

// Traffic Light
// September 2018. MPMC Workshop
// Open source. Have a good fun!
//https://pastebin.com/xz7icMbD
int RL = 7; // int + variable name + = + pin number + ;
int YL = 6;
int GL = 5;
//
int RR = 4;
int YR = 3;
int GR = 2;
//
void setup() {
  pinMode (RL, OUTPUT); // pinMode + ( + variable number + , + type pin + ) + ;
  pinMode (YL, OUTPUT);
  pinMode (GL, OUTPUT);
  //
  pinMode (RR, OUTPUT);
  pinMode (YR, OUTPUT);
  pinMode (GR, OUTPUT);
  //
}
// put all the low output pins. The tension will be zero.
void loop() {
  digitalWrite (RL, LOW); // digitalWrite + ( + variable name + , + pin high or low + ) + ;
  digitalWrite (YL, LOW);
  digitalWrite (GL, LOW);
  digitalWrite (RR, LOW);
  digitalWrite (YL, LOW);
  digitalWrite (GR, LOW);
  // let's start the traffic light
  //we turn on the two green LEDs
  digitalWrite (GL, HIGH);
  digitalWrite (GR, HIGH);
  //the LEDs remain on for 4 seconds
  delay (4000);
  //yellow LEDs on and green LEDs on
  digitalWrite (YL, HIGH);
  digitalWrite (YR, HIGH);
  delay (2000);
  //
  digitalWrite (YL, LOW);
  digitalWrite (GL, LOW);
  digitalWrite (YR, LOW);
  digitalWrite (GR, LOW);
  //
  digitalWrite (RL, HIGH);
  digitalWrite (RR, HIGH);
  delay (4000);
}