Can you change the word Three to the word Seven in five steps or less with the following rules:

You must exactly replace two letters; one vowel and one consonant of the word in each step with a different consonant and a different vowel. The new vowel or the new consonant can go in the place of either the consonant or the vowel in the preceeding word. You cannot replace the letter with exact same letter. Replacing the vowel and the consonant with either 2 vowels or two consonants not allowed.

The new word must be in the Merriam Webster dictionary.

No anagrams or rearrangements or Proper nouns or abbreviations or acronyms.

I think this can be done in 5 or 4 steps.

  • $\begingroup$ To be explicit: you can't leave either the vowel or the consonant alone when doing one step? $\endgroup$
    – Gareth McCaughan
    Jan 19, 2021 at 15:03
  • $\begingroup$ (even if you're swapping their places) $\endgroup$
    – Gareth McCaughan
    Jan 19, 2021 at 15:04
  • $\begingroup$ So if the word is Road then Role is fine "a" changed to L and d to e. The new word is a 4 letter word with 1 vowel and 1 consonant replaced by another vowel and consonant. But if you change the d to a or o it is fine too. But you must change 2 letters ( 1 vow and 1 cons). $\endgroup$
    – DrD
    Jan 19, 2021 at 15:11

1 Answer 1


Here are the steps:


T H R E E --> T I R E S


T I R E S --> S E R E S


S E R E S --> S I R E N


S I R E N --> S E V E N

  • $\begingroup$ Great job @kristinalustig. That must be optimal $\endgroup$
    – DrD
    Jan 19, 2021 at 15:29
  • 5
    $\begingroup$ "sores" instead of "seres" also works and seems a bit more common. Not a native speaker, though. Or perhaps I'm just sore you beat me to it ;-) $\endgroup$ Jan 19, 2021 at 15:52
  • $\begingroup$ @PaulPanzer Ah, good call. I had "seres" at first because I was trying not to change the e's again, but I had to anyway, so I could have changed it to the more common word! $\endgroup$
    – kristinalustig
    Jan 19, 2021 at 19:00
  • $\begingroup$ Also from seres or sores you can also go to rot13 fnirf $\endgroup$
    – DrD
    Jan 19, 2021 at 19:12

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