How to apply the principle of encapsulation to this code?

Question

Java

class Fox {
    public static void main(String[] args) {
        int a = 1;
        int b = 2;
        int c = 3;
        int d = 4;
        for(a=1; a<4; a++){
         for(b=2; b<7; b++){
             for(c=3; c<10; c++){
              for(d=4; d<20; d++){
                  System.out.println("   " + a + b + c + d);
              }   
             }
         }   
        }
    }
}

Answer 1

There's not much to encapsulate, to be honest.
You have local variables inside the main() method, and there are a couple of loops that work with these variables.