Word Sprout

Some friends and I made up a fun game. We played with tiles, but they're not strictly necessary. Here are the essential bits:

The Core Rules

  1. Players take turns adding letters to a central string of letters. New letters may be added to either end or anywhere in the middle.
  2. At the end of each player's turn, the string of letters must be a substring of a word.
  3. Players who cannot play on their turn are out, and play continues to the next player.
  4. The last player left in the game is the winner.

The Other Rules

  1. If you're playing with tiles, and there are no more tiles in the pot of a certain letter, you can't play that letter.
  2. If you play out of turn, you are out. If the next player plays before people notice your illegal play, you luck out and play continues as though your turn were legal.
  3. The player whose turn it is may challenge the previous play. If the challanged player shows that the play was valid (such as by telling everyone a word of which the central string is a substring), the challenger is out. If the challenged player does not show the play to be valid, that player is out.
  4. When a player is out, their play (if they played something which caused them to lose) is undone and play resumes with the next player.

    Here, "next player" means the player who would have been next had the loser not been involved. So if they played out of turn, the play order is not affected, and if they altered the order of play (such as by reversing it) with their move, this effect is undone.

    Undoing a play means undoing all its effects on the game, except the effect of causing the loser to lose.

Substring is defined as a consecutive run of letters found inside another run of letters. For example, "bcd" is a substring of "abcde", as are "a", "de", and even "abcde".


Here's an example with two players.

1: O
2: OA
1: OAT

Player 2 wasn't able to add a letter to "bombastic", so Player 1 wins. At each step, the string does not need to be a word, it just needs to be a substring of a word. For example, although "omat" isn't a word, it's fine because it's a substring of "tomato" and "aromatic".

Often when I play, I'm forced into a word that causes me to lose, and I wonder whether I had better options. I'm a geek, so I wrote a program to tell me. The obvious and easy thing is to list all words that a given string is a substring of, but what I really want to know is whether I could legally add a letter, not whether the last person could. So I wrote a program that, given a substring, lists all valid goal words that contain something I could make by adding a single letter to the original string. You can try it out with this form, but you'll have to forgive my meager dictionary.

And of course, you can have the program too.

Valid Goal Words

A string is valid if it is a substring of a goal word. In the basic rules, any real word is a valid goal word. As with many word games, players need to agree on what constitutes a valid word.

We played that goal words are only valid if they could be reached. With the basic rules above, the only way a word couldn't be reached is if there weren't enough tiles to spell the word. Variations that restrict valid strings can make this more complicated; there may be a real word that can't be reached by a series of valid moves.


Due mostly to the metamorphism rule (explained below), we came up with a bunch of optional rules. Some worked well, some complemented other optional rules, a few didn't work well, and a couple never came up.


  1. Whoever wins a round gets to make a new rule or remove an existing one.

Valid Strings

  1. A string is valid only if it forms a complete word, not just a substring.
  2. A string is valid if it could be made a substring of a word by adding vowels.
  3. No plurals ending in "es" or "s" are allowed. If a word can be justified on other grounds though, it is allowed. For example, "bikes" is fine because it's a conjugation of "to bike".
  4. The first three letters played must be consonants.
  5. There may not be more vowels than consonants.
  6. After the first three letters are played, no one may add a consonant to the beginning of the string.
  7. If the string is a palindrome at the end of any turn after or including the third, on all subsequent turns strings are only valid if they are palindromes. Players may play one or two letters on their turn.
  8. A goal word does not need to be reachable.


  1. Any player may challenge the validity of the previous play. If the play was valid, the challenger is out. If the play was not valid, the challenger wins the round. Players may not challenge themselves.

Play Order

  1. When a vowel is played, the order of play reverses. (For example, switching from clockwise to anticlockwise around the circle of players)

Team Play

  1. Players are grouped into teams and win in anyone on their team wins.

Vowel Collections

  1. When someone plays a vowel, that player also adds the same vowel to their collection unless they already have it. The first player to collect all five vowels wins (and turns them in). If there's only one tile of a certain vowel in the pot, you may play that tile, but you don't get one for your collection.
  2. Collections persist across rounds. When a round is over, players keep their vowels.
  3. Even when collections persist across rounds, when anyone wins by collecting five vowels, everyone turns in their vowels.
  4. When someone plays a vowel they already have in their collection, they lose the one in their collection.


  1. Players may start a new word that intersects an existing string, but only if all existing strings are complete words of at least five letters. (It's not really playable without the extra constraint.)
  2. A player wins if they create a closed shape with a hole.

This page first reared its ugly head on 3 Oct 2000.