Add a letter
Remove a letter
Replace a letter
Swap two letters
So, an example would look like this:
HOLE
Replace the L with an S.
HOSE
And so on... Also, the word can exceed four letters. However, you may NOT immediately reuse a word. To take the example above, where HOSE was changed to HOES, you may not change the letters around to make HOSE again. Not even you, programmer!Swap the E and the S.
HOES
Starting word: LOOK