“Do not open until Christmas”, enforced

The heading on this card says “Don't open till Christmas”, and the lock makes it true. Set the lock to Christmas morning and send the link any time in December: opened early, the card shows a countdown and will not scratch. On the day it unlocks by itself. The lock follows the clock on each person's own phone, so it is Christmas morning for the cousin in Sydney and the aunt in Toronto when it is their morning. The “Remind me” button on a locked card saves a calendar entry for it.

Making the card

1. Start from “Christmas”: gold foil on a green card, stars around the edge, more stars when it is revealed.
2. Write what is under the foil — a wish, or what the present is. For red instead of green, pick it under “Colour”.
3. Add a small line if it helps: “Under the tree, blue paper”.
4. Sign it. For children, the name can be “Santa”.

Presents that are not under the tree

Some presents cannot be wrapped: tickets, a trip in the new year, a bicycle hidden in the garage, the news that you are coming home. The card gives them a moment on Christmas morning. For a present with a story, add cards to the link — they are scratched in order, and only the last one sets off the celebration.

A five-day countdown

A link holds up to five cards, but each link has one lock. For a small advent countdown, make five separate cards — a line of a poem, a clue, a chocolate hidden somewhere in the house — lock each to a different morning from the 21st to the 25th, and send all five links at once.

Secret Santa

For an office or family draw, make one card per person with the name they have drawn under the foil and send each link privately. Nobody can read the name from the link itself: the message inside it is scrambled. Whoever organises the draw will know all the pairings, as with paper slips.

Far-away family

For grandparents in another country, set “Language they will read” if English is not what they read most easily, and use the longer note — up to 600 characters, opened after the scratching — for the news of the year. After the reveal they can save the card as a picture or a short video.