Slitherlink vs Pencil Logic

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, two-finger pan, iPad and Apple Pencil support • 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.

Pencil Logic is an offline collection of seven classic Japanese pencil-logic puzzles: Slitherlink, Masyu, Hashi (Hashiwokakero), Nurikabe, Futoshiki, Shikaku and Kakuro. Every board is generated on your device with a guaranteed unique solution, so there's always a fresh puzzle waiting, no wifi needed. Free to play with ads; a one-time purchase removes them for good. SEVEN PUZZLES, ONE APP • Slitherlink: draw one loop through the dots so each number says how many of its sides the loop uses. • Masyu: draw one loop through every pearl, straight through white pearls, with a turn at black ones. • Hashi (Hashiwokakero): connect every island with bridges matching its number, no crossings. • Nurikabe: shade one connected wall so each number is an island of exactly that many cells. • Futoshiki: fill the grid with 1 to n, obeying the greater-than signs between cells. • Shikaku: cut the grid into rectangles, one per number, each of exactly that size. • Kakuro: fill the white cells so every run adds up to its clue, no digit repeating in a run. BUILT TO ACTUALLY PLAY • Four difficulties per puzzle, Easy through Expert, so there's a fair board whether you're learning the rules or hunting a real challenge. • Undo and redo, a mistake check, and a hint when you're stuck. • Auto-save: close the app mid-puzzle and pick up exactly where you left off. • Left-handed layout and haptics, your choice in Settings. • Light and dark mode, matching your system automatically. A DAILY CHALLENGE FOR EVERYONE • One puzzle a day, the same board for every player, rotating through all seven mechanics. • Build a streak and see your last seven days at a glance. FREE TO PLAY, HONESTLY • Play every puzzle and every difficulty for free, supported by ads between puzzles. • The first hint on any board is always free. • A one-time purchase removes ads completely and makes every hint free, no subscription. No account, no sign-in, and no internet connection needed to play. Whether you know these puzzles by name already or you've never tried a Japanese logic puzzle before, Pencil Logic is built to teach the rules on the board itself and keep a fresh one ready every time you open it.