import objectdraw.*;

// A list of VisibleImages.  This interface
//  captures what is common about all lists.
public interface StackInterface {
    
    // Returns true if the stack is empty
    public boolean isEmpty();
    
    // Returns the first image in the list
    // Pre-condition: 
    //     the list is not an empty list.
    public VisibleImage getFirst();
    
    // Returns the rest of the list, after
    // the first image.
    // Pre-condition: 
    //     the list is not an empty list.
    public StackInterface getRest();
    
}