Zip

How to play Zip

1. Draw a single line that starts at 1 and ends at the highest number.
2. The line must pass the numbers in order: 1, then 2, then 3, and so on.
3. It has to visit every cell exactly once. No cell may be left empty.
4. Walls (thick lines between cells) cannot be crossed.
5. Drag from the head of the line to extend it. Drag backwards, or tap an earlier cell, to undo.