Make a memory game

1. 01Choose what goes on the cards: photos, picture symbols or a list of word pairs. 4 to 40 pairs.
2. 02Set size, border, corners and back. The preview shows the real PDF right away.
3. 03Download the PDF, print it on both sides on sturdy paper and cut it out.

Playing. Lay all cards face down. Whoever's turn it is turns over two cards. If they match, the kid keeps them and goes again; otherwise they are turned back over. With photo and word or problem and answer, two different cards belong together. If the same card is in two pairs (for example the answer 5 twice), the page tells you, because the card then matches both.

Photos. Every photo is cropped to a square. You choose the crop area for each photo: grab the picture and drag, or use the arrow keys, plus the zoom. Photos from a phone are turned the right way up. The work is done with a reduced copy of at most 1200 pixels on the long side. How many dpi the crop area has on the card is shown below it; below 150 dpi it gets soft in print, and the page tells you. Only the pixels go into the PDF, no camera data and no location. HEIC photos from an iPhone are usually opened only by Safari; if your browser cannot open a photo, the page tells you. If you set “Most Compatible” on the iPhone, it saves JPG.

Word pairs. One line per pair, left and right separated by a semicolon, for example A;a, cat;chat, 3 + 4;7 or 5;#5 for the number and a dot picture. Up to 6 dots they are arranged like on a die, above that in rows of five. The type is set as large as fits on the card, long words get smaller or wrap. If a word does not fit on one line even when small, it is split, and the page names it. The type is Helvetica: umlauts and ß work, letters like ł become the base letter, emoji are missing in print. The page shows this beforehand, too.

Picture symbols. 50 simple motifs like sun, apple, car or ship, drawn from lines in code and printed as an outline so that kids can color them in themselves. Which ones appear is decided by the No.; “Roll again” takes others.

Back and double-sided printing. Behind every page of cards, the PDF has its back. Print on both sides and let the sheet turn on the long edge, which is usually the default. Left and right swap in the process; that is why the backs in the PDF are arranged mirrored, so that they land exactly behind their card. Printers often shift the back by 1 to 2 mm. A pattern forgives that, a frame would show it; that is why there is none on the back. Do the test sheet first: print on both sides and hold it against the light. If the crosses lie on top of each other, everything fits. Without a duplex printer, you print the odd pages first, put the stack back in and print the even ones; which way around, the test sheet shows you. “None” leaves the backs out, for example if you glue the cards onto cardboard.

Cutting. Square cards lie edge to edge, one cut separates two cards. The crop marks on the outer edge show every cut line. Round cards have a 4 mm gap and a thin line all around, which you cut along with scissors. At least 10 mm stays free all around on the sheet. Sturdy paper from 160 g/m² plays better, and you cannot see the pictures through it; whether your printer takes it in is in its manual.

Saving. “Save to a file” writes pairs, settings and, if you want, the photos into a JSON file on your device. It contains the words and names in plain text and the photos as image data: keep the file where you keep your other documents for the group. If you saved without photos, you choose them again when loading; the words then get the photos in the order in which you select them.

Limits. 4 to 40 pairs, so at most 80 cards, A4 portrait only. Cards only square in 4, 5, 6 or 7 cm. Photos up to 40 MB per file. If the browser's memory is not enough for a photo, the page tells you and leaves the photo out. A cut-off image file is often shown only in part by the browser; so check the preview. Whether front and back line up exactly depends on the printer. The colors of the photos depend on the printer; everything else is printed black on white.