Doublets is a word game invented by Lewis Carroll. The rules were published in Vanity Fair Magazine in 1879:
The rules of the Puzzle are simple enough. Two words are proposed, of the same length; and the Puzzle consists in linking these together by interposing other words, each of which shall differ from the next word in one letter only. That is to say, one letter may be changed in one of the given words, then one letter in the word so obtained, and so on, till we arrive at the other given word.
I love the poetic flow this game creates, and have been using it in my current work.
The overprinted version is a photoshop experiment. I will try the real thing on press, using colour overprinting.