Slitherlink

Connect the dots with horizontal and vertical lines to form one single closed loop. The loop never crosses or touches itself and has no branches.

• A number tells how many of the cell's four sides are part of the loop.
• Cells without a number can have any number of loop sides.

Controls

• Tap a line between two dots to cycle: empty → line → ✕ (definitely no line) → empty.
• Right-click or long-press toggles a ✕. Drag along the grid to draw many lines at once.
• Ctrl+Z undoes. Check highlights wrong lines, Hint sets one correct line.

Numbers with too many (or too few possible) lines and dots with branching or dead-end lines are shown in red. Every puzzle has exactly one solution.

Tips

A 0 means all four sides are ✕. Two 3s side by side share a line that is drawn, plus the outer parallel lines. A 3 in a corner of the board has both corner sides drawn. Every dot has either 0 or 2 lines — a dot with one line and only one open direction must continue that way.