The word ladder game was invented by Lewis Carroll in 1877. The idea is to begin with a start word and change one letter at a time until arriving at an end word. Each word along the way must be an English word. For example, starting from FISH you can make a word ladder to MAST through the following ladder: FISH, WISH, WASH, MASH, MAST Write a program that uses recursion to find the word ladder given a start word and an end word, or determines if no word ladder exists. Use the file words.txt that is available online with the source code for the book as your dictionary of valid words. This file contains 87314 words. Your program does not need to find the shortest word ladder between words, any word ladder will do if one exists.

This is from Walter Savitch, Java: An introduction to problem solving and programming. It's from Chapter 11, number 8. Please solve this recursively using relatively simple methods. Thank you.