Solution to Challenge 1

(a) Fold the bottom edge up to the top edge, then open it out
- A valley fold line (dashed) across the middle of the paper, parallel to the edges.
- A fold-and-unfold arrow: it goes from the bottom edge up to the top edge and comes back, ending with the paper open. The result is a pre-crease, a horizontal line across the centre.
- This is the book fold from the vocabulary table, used as a pre-crease.

(b) Fold the left corner behind the paper to the centre
- A mountain fold line (dash-dot), cutting off the left corner.
- A fold arrow pointing behind the sheet, with its tip at the centre. Check the head style in your source: a hollow head usually means mountain.
- Folding a corner to the centre is the same move you do four times for a blintz fold, here done once and behind the paper.

(c) Turn the paper over, then rotate it a quarter turn clockwise
- A turn-over arrow, looping over a short line beside the model.
- Then, in the next picture, a circular arrow marked with a quarter turn (a "1/4" or a small 90 degree note), pointing clockwise.
- These are two separate steps, so each gets its own picture.

Checkpoint: the paper you fold should match the picture after each step. If it does not, re-read the line type before the arrow.