Slitherlink – Loop Puzzle

Slitherlink, the classic logic puzzle — drawn like pen on paper.

The rules are simple.
Each number counts the lines surrounding its cell. Satisfy every number while drawing one single closed loop — no branches, no crossings — and the puzzle is complete. It looks easy, and then the logic gets delicious.

Every puzzle has exactly one solution.
Guessing is never required: every generated puzzle is mathematically verified to have a unique answer. Difficulty names mean something here, too — we measure the depth of reasoning each puzzle actually needs, and only serve ones that earn their label.

■ Features

• New to Slitherlink? A hands-on tutorial teaches the rules on a tiny practice board
• Four difficulties — from Easy 5×5 to Expert 12×12
• Daily Puzzle — the same board for everyone each day, with an attendance calendar and streaks
• Paper-quiet design — an ink-and-paper ledger look, in light and dark
• Comfortable controls — tap to draw, long-press to mark ×, drag along the dots
• Room for big boards — pinch to zoom and pan with two fingers
• Mistake-proof — unlimited undo/redo and automatic saving
• Track your progress — best and average times per difficulty

For the moments you want quiet focus, one board of Slitherlink is enough.