никак не могу понять
package com.javarush.task.task23.task2312;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

public class Snake {
    private List sections;
    private boolean isAlive;
    private SnakeDirection direction;
    private SnakeSection head;

    public Snake(int x, int y) {
        sections = new LinkedList<>();
        head = new SnakeSection(x,y);
//        sections.add(0,head);
        isAlive = true;
    }

........