Use an old Christmas Card or Greetings Card that you’d usually throw away or put in the recycling

Cut a piece off the card about 7-8 cm wide, and as long as you like
Fold the card in half longwise with the picture on the outside
Cut slits about half a cm wide diagonally up the card, from the folded side, but don’t cut all the way through – leave at least 1 cm at the end
Open out the card flat
Start folding down the upside down V shapes from the top. Fold one, then miss one, then fold one, and so on
Tuck the pointed end of the folded down V behind the one below to lock it
When you reach the bottom, stop
Stick the card onto an slightly bigger card to make a bookmark, or a new card