How to play
- Fill the grid with numbers 1 to 16.
- The next number must be exactly 1, 2 or 3 squares away.
- Moves are horizontal or vertical only.
- No diagonals.
- Grey shades show the distance to the next number.
- White = 1 square, light grey = 2, dark grey = 3.
- The final number is shown in bold.