How we make our puzzles

A fair grid has real words, one answer and a scramble that rewards careful play. Here is how we check that for every grid.

Where do the words come from?

Answers come from the common word lists in SCOWL, a set of English word lists sorted by how often words are used. We only keep words that also appear in WordNet, the English dictionary built at Princeton University. That keeps out rare words, short forms and names.

We also remove rude, violent and upsetting words, so the grids suit all ages. The 5×5 grids use five letter words. The 7×7 grids use seven letter words.

How is a grid built?

Our program fills the waffle shape so that every across word and every down word is real, and every shared letter fits both words. Once a word is used, it cannot come back for at least 120 days. That keeps the daily grids fresh.

How do we know there is only one answer?

Before we accept a grid, the program tries every way the starting letters could spell valid words. For this test it uses a much bigger word list that also has plurals and past tenses. If the letters can spell a second full grid, we throw the grid away.

Why does every grid take exactly 10 or 20 swaps?

We scramble the letters in a set pattern so the fewest swaps needed is exactly 10 on the 5×5 grid and 20 on the 7×7 grid. The count allows for repeated letters. So five stars is always possible, and never easier than we say.

Where do the hints come from?

The clue for each word is its first meaning in WordNet 3.1. The swap by swap route on each hints page is worked out from the grid itself, so it is always one of the shortest routes.

When do new grids go live?

A new 5×5 grid and a new 7×7 grid go live at midnight UTC each day. We never change a grid after it goes live. If you think a word does not belong, tell us and we will look at it.