Zerdly Memory Cards

Turn a card over, then another. A matching pair stays face up and you go again; a mismatch turns back over after a moment and, with two players, the turn passes.

While two cards are face up the board is locked, so a third tap does nothing. That is a rule rather than an animation — tapping quickly cannot slip an extra card through. The lock is shorter after a pair than after a miss, because you do not need as long to look at something you got right.

Clear every pair to finish. The board records how many moves it took and how long, and your longest unbroken run of pairs.

Tap or click a card. On a keyboard, Tab reaches the board and the arrow keys move between cards; Enter or Space turns one over. Cards never need a hover, so a touchscreen is not a second-class way to play.

There are 32 symbols, and each is an outline — three points up to ten — in one of four fills: solid, ring, split or pierced. No two symbols share both a shape and a fill, so the colour is confirmation rather than information and the game works in greyscale.

Every shape is drawn from geometry rather than from a picture, which is why the same symbol stays crisp on a four by four board and on an eight by eight one.

• Classic 4×4 — Eight pairs. A quick game, and the friendliest place to start. (8 pairs)
• Classic 6×6 — Eighteen pairs. The standard board. (18 pairs)
• Classic 8×8 — Thirty-two pairs, and a real test of what you can hold in mind. (32 pairs)
• Zen — No clock, no moves counter, and mismatches linger. Look properly rather than tap quickly. (18 pairs)
• 90-second sprint — Ninety seconds. How many pairs can you clear? (18 pairs)
• Daily board — The same layout for everybody today. (18 pairs)

Zen is a different game rather than an easier one: it leaves a mismatch up for twice as long and keeps no clock and no move count at all, so nothing is measuring you while you look.

Work along a row rather than tapping about. Turning cards over in an order you can describe to yourself gives you something to remember them by; a random tap gives you a position you will not recall.

When you turn a card you already know, turn its partner second. The second card is the one you are trying to place, and pairing a known card with an unknown one wastes the half of the turn you could have spent learning something.

The shape is easier to hold in mind than the colour. “Seven points, ring” sticks; “the greenish one” does not, and there are four greenish ones.

The whole game runs in your browser. Ordinary boards are shuffled with your browser’s cryptographic random generator; the Daily comes from the UTC date, so everybody gets the same layout. Nothing about your game is uploaded, and no account is needed.

A half-finished board is saved only where picking it up later would be the same game. A sprint is not saved — its score is ninety seconds of real time — and neither is a two-player game, since the board cannot know which of you is still here. The game says so on screen rather than losing your board without explanation.

Your records, your saved board, your Daily history and your sound and motion settings are stored in this browser only. Nothing here asks for a name or an email, and the button on this page removes all of it — and only this game’s share of it.

Is it really free, and do I need an account?

Yes, and no. There is no sign-up, no trial and nothing to buy. The game runs in your browser and never sends your games anywhere.

Can I tell the cards apart without colour?

Yes. Every symbol is a distinct outline — three points up to ten — in one of four fills, and no two share both. The colour is a third signal rather than the first, so the whole game works in greyscale and works for anybody who cannot separate two of the hues.

Why can I not turn a third card over?

Two cards face up is the whole of a turn, so the board is locked until they settle. That is a rule rather than an animation, so tapping quickly cannot slip a third one through — and the lock is shorter after a pair than after a miss.

Is my half-finished board saved?

On the boards where picking it up later would be the same game, yes. A sprint is not saved, because its score is ninety seconds of real time and a game resumed tomorrow would not be that game. Two-player games are not saved either — the board has no way of knowing which of you is still in the room.

What is the Daily board?

One layout for everybody, seeded from the UTC date. It changes at midnight UTC rather than at your local midnight, and your run of cleared days is kept in this browser.

Where is my record kept?

In this browser, and nowhere else. Each board keeps its own, because they are not comparable — fewer moves is better on a Classic board, more pairs is better in a sprint, and Zen counts neither. The button on this page erases all of it.

• CodebreakerDeduce a hidden code from exact and misplaced feedback.
• Mahjong SolitaireClear the layout by matching free tiles in pairs.
• NonogramDeduce a picture from the numbers along its edges.