Change one word to another

I'm looking for someone to write a program to "morph" one word into another by changing one letter at a time. For example: Change the word WARM to the word COLD warm wOrm (Change the "a" in the word warm to "o" thus making the word worm.) worD (Change the "m" in the word worm to a "d" thus making the word word.) Cord (Change the "w" in the word word to a "c" thus making the word cord.) coLd (Change the "r" in word cord to an "l" thus making the word cold.) --------------------------- Change the word BIRD to WING bird bind wind wing A Google search of "word ladders" or "change one word into another" will give you web sites with these kinds of programs. I just want the option of entering my own words. I'm only interested in using four-letter words. No profanity, no foreign words, no proper nouns, no technical or weird words. This is a game for kids so I want to keep it simple. I would like to be able to input a beginning word and an ending word and have the program generate a series of "interim" words. I don't know if there's an elegant way to do that, but it seems that if you had a list of several thousand four-letter words, it would be possible to write a program that does a "brute force" search to see which words provide a path to the ending word. Of course, there is likely to be more than one possible path but I would only need the program to generate one path at a time. I would like it to have the option of searching the same two words for an alternative path. Hopefully, this gives you enough to quote the job.