public class Thing {
  public static int a = 5; // class variable
  public int b = 0; // instance variable
  
  public Thing (int initb) {
    b = initb; 
  }
  
  public static void scale (int s) { // class method    
    a = a*s;
  }
  
  public int f (int x) { // instance method
    return a*x + b;
  }
  
  public static void main (String[] args) {
    Thing thing1 = new Thing(1);
    Thing thing2 = new Thing(2);
    System.out.println("thing1.f(10)=" + thing1.f(10) 
                       + "; thing2.f(10)=" + thing2.f(10));
    scale(2);
    System.out.println("thing1.f(10)=" + thing1.f(10) 
                       + "; thing2.f(10)=" + thing2.f(10));
  
  }
}