How daily puzzles work: one seed, one board for everyone

A daily puzzle is a small promise. The board you see today is the same one your friend sees across town, and the same one a stranger is solving on the other side of the world. Nobody gets an easier version, and nobody has to download today's board from a central list. This article explains how that works on Duo Games, and the handful of rules that make a daily challenge feel fair.

A date becomes a number

Computers are very good at following instructions and very bad at being truly random. Games get around this with a pseudo-random number generator: a short formula that takes a starting number, called the seed, and turns it into a long sequence of numbers that look random. The useful part is that the same seed always produces the same sequence.

Our daily boards start from a piece of text made of the game's name and today's date, such as worm-escape:2026-10-29. A quick hashing step turns that text into a single whole number, and that number seeds the generator. From then on, every decision the game makes for the board comes from that sequence, in order: where each worm curls up, which shape you are dealt next, where each color lands.

Why everyone sees the same board

The seed is built only from the game and the date. Nothing about your phone, your location or your browser goes into it, so two devices that have never been in contact produce identical boards. There is no server deciding what you get, which also means the daily puzzle works offline once the page has loaded.

There is a second, less obvious requirement. The game has to ask for random numbers in exactly the same order every time. If a sparkle effect or a sound pulled a number from the same generator in the middle of building the board, two players with different settings would drift apart. So the puzzle logic uses the seeded generator, and purely decorative effects use their own separate randomness.

When does today start?

There are two reasonable choices. One is a single global changeover, the same instant for everyone. The other is midnight in each player's own time zone. We use local midnight, so the daily board changes when your calendar day does. A player in Tokyo and a player in Toronto both get a full day with each puzzle.

The trade-off is that for a few hours, two friends in different time zones can be on different boards. That is why shared results include the puzzle number, so you can tell at a glance whether you are comparing the same challenge.

One attempt that counts

You can replay a daily board as often as you like, but only your first finished run is recorded as your daily result. Practice is welcome. If every retry counted, though, the daily score would end up measuring patience instead of skill, and comparing results with friends would stop meaning much.

Streaks without the pressure

A streak counts the days in a row you finished the daily puzzle. Ours counts back from today, or from yesterday if you have not played yet today, so your streak does not look broken first thing in the morning.

Results stay on your device. There is no account, nothing to log into, and nothing about your play is sent anywhere. The honest downside is that clearing your browser data also clears your streak, so if you care about a long run, avoid wiping site data for Duo Games.

Sharing a result without spoiling it

The share button copies a short block of text, often a little grid of emoji, that shows how you did without giving away the solution. A friend who has not played yet can see that you finished with three stars and a strong score, but not which moves got you there. The puzzle number travels with it, so nobody compares Tuesday's board with Wednesday's.

What makes a good daily board

Not every random board is a good puzzle. Left alone, a generator can produce something trivial, something brutal, or something with no solution at all. Daily generators usually avoid this in two ways.

First, they build boards that are solvable by construction. A common trick is to start from a finished state and scramble it with legal moves, so a path back always exists. Second, they measure the result, for example by counting how many steps the shortest solution needs, and reject boards outside a target range. Because the rejection follows the same seeded sequence, every player still lands on the same accepted board.

Try it yourself

Every daily mode on Duo Games uses one of the ideas above, but each game applies it a little differently:

• Built from the answer. Tile Match first picks an order in which all sixty finds could be collected, then hands out shells and crabs along that order. Sliding Puzzle scrambles its photo with forty real slides, so a way back always exists.
• Checked by a solver. Color Sort lets a computer sort each day's shelf before you see it. Mini Sudoku tries a dozen markets with a solver that only uses steps a person would take, and keeps the one closest to the target difficulty.
• Measured and picked. Worm Escape builds three dozen gardens from the date and keeps the one whose chain of blocked worms comes closest to a target depth.
• The date decides the order. In Block Puzzle it fixes all 21 patches you will be dealt, in 2048 where each new block lands and which way the tray tips, in Bubble Pop both the reef and the order of your pearls, and in Jigsaw Puzzle which photo you rebuild and the shape of every knob.
• The simplest case. Word Guess turns the date into a position in a shuffled list of hand-picked words.

Play today's boards, note your scores, and come back tomorrow. The boards will be new, and they will be the same for everyone who plays them with you.