1.Make two pencil marks where you want the score line on the wrong side of the paper and line up the ruler with these marks. Draw an empty ballpoint pen all the way along the line so that the paper is indented. One blade of an open pair of scissors can be used as an alternative. Draw it lightly along the line so that only the topmost fibres of the paper or card are cut. The scored line will become the inside of the fold.

2.Use both hands to fold the paper or card along the score line – it should fold easily.

3.Once the paper or card has been folded, use a bone folder on its side to press along the fold line to make it sharp. The back of a clean metal spoon could be used in place of a bone folder.