const int BUTTONPin =  3;     
const int YELLOW = 8;      
const int GREEN = 9;
const int RED = 10;

int buttonSTATE = 0;   
int result = 0;      
int LOOPstate = 0;      
   

void setup() {
  pinMode(YELLOW, OUTPUT);   
  pinMode(GREEN, OUTPUT);
  pinMode(RED, OUTPUT);
  pinMode(BUTTONPin, INPUT); 
}


void loop(){
 buttonSTATE = digitalRead(BUTTONPin);  

  if(buttonSTATE == HIGH)
  {              
    delay (75);
    buttonSTATE = digitalRead(BUTTONPin);
    if(buttonSTATE == LOW){           
    result = LOOPstate + 1;        
    }
  }
   switch (result){             
     case 1:                    
       digitalWrite(YELLOW, HIGH);
       digitalWrite(GREEN, LOW);
       digitalWrite(RED, LOW);
       LOOPstate =  result;             
       break;
       
     case 2:
       digitalWrite(YELLOW, LOW);
       digitalWrite(GREEN, HIGH);
       digitalWrite(RED, LOW);
      LOOPstate =  result;
       break;

     case 3:
       digitalWrite(YELLOW, LOW);
       digitalWrite(GREEN, LOW);
       digitalWrite(RED, HIGH);
       LOOPstate =  result;
       break;      

     default:                      
       digitalWrite(YELLOW, LOW); 
       digitalWrite(GREEN, LOW);
       digitalWrite(RED, LOW);
       LOOPstate = 0;                    
       break;         
     }
}