Puzzle: Word Ladders

There's a video to introduce Word Ladders at Byrdseed.TV

The “Puzzle of the day” was always a hit with the students I worked with. The most consistently successful type of puzzle in my class was the Word Ladder or Doublet, invented by Lewis Carroll in 1877 (allegedly on Christmas Day!).

Rules

In a Word Ladder:

  • Players get a starting word and an ending word
  • Starting and ending words must be the same length (PIG and HOG, or CAT and DOG)
  • Players change one letter at a time, attempting to move from the starting word to the ending word
  • Each intermediate step must be a valid word, and no proper nouns allowed!

Examples

Here are a few samples. Note that each step is a word and changes only one letter from the previous word.

FLY to CRY

Get from FLY to CRY in one step.

  1. FLY
  2. FRY (l → r)
  3. CRY (f → c)

CAT to DOG

Turn a CAT into a DOG in two steps.

  1. CAT
  2. COT (a → o)
  3. DOT (c → d)
  4. DOG (t → g)

MAN to APE

Naturally, they can get increasingly complex. Carroll’s MAN to APE is a famous example that takes four intermediate steps despite how short the words are.

  1. MAN
  2. MAT (n → t)
  3. OAT (m → o)
  4. OPT (a → p)
  5. APT (o → a)
  6. APE (t → e)