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4 November 2026

Meet DORIS, the Brains Behind Every Puzzle

Last month we asked you to help name the program that builds every Rigid Digit puzzle. We've made our pick. Meet DORIS: Digit Obsessive, Rigid Integer Solver.

The idea came from Countdown. Since the show's very first episode in 1982, its numbers round has had a machine with a name: CECIL, Countdown's Electronic Calculator In Leeds, which picks the target. We loved that, and thought the program quietly building our puzzles every day deserved the same. There's more about CECIL, and the very first target it picked, in our earlier post.

DORIS was a late entry, but it ticked every box. Every word earns its letter. Digit and Rigid are both in there. It fits on five number tiles. And it sounds a bit nerdy, like someone who has been quietly running the numbers since 1982, which feels right for an heir to CECIL.

Thanks to everyone who weighed in. CocoTheDog made a strong case for HARDY and GRID, and MoguTheCat campaigned loudly for EDITH and Rigidy McDigitface. EDITH came close. Rigidy McDigitface, sadly, still doesn't spell anything.

What DORIS does

For every day's puzzles, DORIS deals out a set of numbers for each level, then tries every way of combining them: every pair, every operation, both ways round. That's thousands of possible routes for each puzzle. She only keeps a puzzle once she has checked every one, so there's always an exact answer for you to find. She does the solving so you know a solution exists, never to hand it to you.

Knobs and levers

DORIS isn't just a random number picker. Behind her is a set of knobs and levers, and we can and do use them to fine-tune each day's puzzles. A few of them:

• The tiles. How many of the 25, 50, 75 and 100 tiles each level gets, and how high the goal can go. Easy gets two of them, Medium one, and Hard and Extreme none at all.
• The length. How many moves the shortest solution takes. DORIS checks every route, not just the one she had in mind, so an accidental shortcut can't sneak in.
• The number of solutions. Hard has between 9 and 18 ways to solve it. Extreme has exactly one.
• The operations. We balance the mix across the days, so you get your fair share of subtraction and division, not just adding and multiplying.
• No padding. A × 1 or ÷ 1 never counts as a real step.

Some knobs only exist because of you. When your solve times showed Medium was taking longer than Hard, we gave DORIS a new rule: every Medium puzzle needs at least one get-close-then-nudge route. On that rule's very first day, she served up 102 from 10, 10, 1, 6 and 75, which you could solve by adding up every tile. So now there's a rule against that too.

Not handmade, but hand-tuned

Some daily puzzles are made entirely by hand. Over at the New York Times, Connections is put together by its editor, Wyna Liu, and you can feel the care in every one. We don't make ours by hand. But DORIS isn't a black box spitting out numbers either. Every rule she follows is there because we played her puzzles, watched how you played them, and turned a knob. Not handmade, then, but lovingly fine-tuned.

So next time you crack a puzzle, give DORIS a little nod. She has already found every answer, and she's rooting for you to find one. Loved a puzzle, or think she got one wrong? Tell us in the comments below.