Traffic Lamp

1void setup() {
2  pinMode(2,OUTPUT);
3  pinMode(3,OUTPUT);
4  pinMode(4,OUTPUT);
5}
6void loop() {
7  digitalWrite(2,HIGH);
8  digitalWrite(3,LOW); 
9  digitalWrite(4,LOW);  
10  delay(2000);
11  digitalWrite(2,LOW);  
12  digitalWrite(3,HIGH);
13  digitalWrite(4,LOW);  
14  delay(300);
15  digitalWrite(2,LOW);  
16  digitalWrite(3,LOW);  
17  digitalWrite(4,HIGH);
18  delay(2000);
19  digitalWrite(2,LOW);
20  digitalWrite(3,HIGH);
21  digitalWrite(4,LOW); 
22  delay(300);
23}