Linelet puzzle levels, from beginner to advanced

Linelet puzzle levels climb in two ways: the boards get bigger, from 5x5 up to 13x12, and the lines get longer. The core rule never changes. In Linelet, you join each pair of matching ends with a line that covers exactly the number shown, counting both ends, and fill every open square.

What makes a board harder isn't always what you'd guess, so here's the whole library, from the first board to the last.

The library at a glance

• 862 boards in 21 packs. The first two packs, 50 boards, are free, and the other 19 open with a one-time $2.99 purchase.
• Sizes run from 5x5 up to 13 across by 12 down. Most boards are square, and some are tall or wide, such as 7 across by 10 down and 10 across by 7 down.
• 612 of the 862 boards have walls: squares that aren't part of the board.
• Every board carries a measured label. 36 are Easy, 349 Medium and 477 Advanced, and the 112 hardest Advanced boards are labelled Very hard.

The packs, in order

• First Steps (free, 20 boards): 5x5 to 6x7. Mostly Easy, with a few Medium boards and one Advanced board as a taste.
• Gentle Slopes (free, 30 boards): 5x5 to 7x7, easing into Medium, with more walled boards and three Advanced boards.
• Open Meadow (55): plain 6x6, 6x7 and 7x6 boards at Medium, with no walls at all.
• Crossroads (55): 6x6 to 7x7 boards at Medium, now with walls.
• Tall Timber (45): tall boards at Medium, up to 7 across by 10 down.
• Wide Water (45): wide boards at Medium, up to 10 across by 7 down.
• The Thicket (55): 7x7 boards, where Medium gives way to Advanced.
• The Summit (60): 7x7 and 8x8, all Advanced.
• Deep End (55): 8x8, 8x9 and 9x8 with walls, all Advanced.
• The Vault (50): 9x9 with walls, all Advanced.
• Far Reach (57): 10x10, 10x8 and 8x10 with walls, all Advanced, and 22 of them Very hard.
• Labyrinth (45): heavily walled mazes from 8x8 up to 9x9, 10x8 and 8x10, a mix of Medium and Advanced.
• High Ridge (30): 11x11 and 12 across by 11 down, with walls, the harder Advanced pack.
• Mystery Numbers (40): 7x7 and 8x8, where some numbers are hidden and you work out how long those lines are.
• Turns and Straights (40): 7x7 and 8x8, with dots that make a line turn or go straight through that square.
• Bridges (40): 7x7 and 8x8, with bridge squares where one line crosses over another.
• Shapes (40): shaped boards on 10x10, 11 across by 9 down and 11x11 grids.
• Into the Fog (40): 7x7 and 8x8, where most of the board starts hidden and clears as you draw.
• Storm Front (20): 12x12 and 13x12, all Very hard, with fog and mystery numbers on every board.
• Crossfire (20): 11x11 and 12x12, all Very hard, with bridges and mystery numbers on every board.
• The Gauntlet (20): 12x12 and 13x12, all Very hard, with bridges, fog and mystery numbers together.

Do bigger boards have more lines? Not many more, just longer ones

You'd expect a 10x10 board to be crowded with pairs. It isn't. A 5x5 board in Linelet has 5 or 6 lines, and a 10x10 has between 5 and 11. What grows is the length: on a 5x5 the longest line covers 6 squares, but on a 10x10 a single line can cover 25. The Very hard boards, up to 13x12, can have 17 lines, and one line can cover 43 squares.

That's where the difficulty lives. A short line only has a handful of possible routes. A long one can wander almost anywhere, so you can't pin it down by staring at it. You work out where it goes by working out where everything else can't.

Stage one: small boards

The 5x5 and 6x6 boards are mostly Easy. They teach the rules and two habits worth keeping for good.

First, count the gap between a pair's ends: if the number matches the shortest possible route, the line is forced. Second, the numbers on a board always add up to the number of open squares, which makes a quick check when something feels off.

The free packs ramp on purpose. Boards are ordered by their measured difficulty, but a new shape turns up within the first few boards and a genuinely Advanced board appears partway through. You get a feel for what's ahead without being thrown in at the deep end.

Stage two: walls and new shapes

Walled boards, tall boards and wide boards come next. A wall acts like an extra edge. A square next to a wall behaves like an edge square, and a square boxed in by walls behaves like a corner, with very few ways in or out. Walls can split a board into rooms, and the lines that start in a room must fill it exactly.

This is the second surprise: walls usually make a board easier, not harder, because every wall removes routes. That's why the heavily walled Labyrinth pack is partly Medium. The hardest boards in Linelet get their difficulty from open space.

Tall and wide boards read differently too. Long lines tend to run along the long side, and the short side fills up quickly, which gives you somewhere to start.

Stage three: 7x7 and 8x8

Advanced begins here, and several long lines now compete for the same squares. Three habits from our tips for solving number line puzzles help most:

• The detour rule. A line can only be its shortest length, or two more, or four more. If a line is one square off, no wiggle will fix it.
• Watch for pockets. Before you commit a long line, check it doesn't seal off a group of squares that nothing can fill.
• Short lines first. Place the lines with the fewest possible routes, and each one narrows the rest.

Stage four: 9x9 and 10x10

The biggest boards aren't quick. Treat them as something to come back to over a day or two. Linelet saves a board you leave halfway, so you can close it and return with fresh eyes.

When you're stuck, hints climb gently: first the line worth thinking about, then one square its route must use. Those two are free on every board, and the one-time purchase adds a third that shows the whole line.

On big boards, it also pays to count rooms. Walls and finished lines split the board up, and each region's remaining lines must add up to its size exactly. If they don't, something earlier is wrong.

Stage five: twists and Very hard boards

After the main packs comes High Ridge, a harder Advanced pack of 11x11 and 12 across by 11 down boards. Then five twist packs each add one new rule: hidden numbers, turn and straight dots, bridges, shaped boards or fog. They mix Medium and Advanced boards, so each one is a good place to learn its twist on its own.

The three Very hard packs, Storm Front, Crossfire and The Gauntlet, put two or three twists on one big board, up to 13x12. Very hard is the top of Advanced: every board there scores 90 or more on the same measure as the rest of the library. Take them slowly, and come back to them over a few days.

How are Linelet puzzle levels measured?

Nobody picks Easy, Medium or Advanced by hand. Each board is scored on what it actually contains: how many routes each line could take on its own, how many lines have only one route, how much the lines compete for the same squares, how much longer the lines are than their shortest routes, and how much searching a computer solver needed.

That score is compared with what's typical for a board with a similar number of open squares, plus a small nudge for size itself. So a tricky small board can outrank a plodding big one.

Every board has also been checked to have exactly one answer. We explain why that matters in why a puzzle with exactly one answer feels fairer.

When should you move up a level?

Try the next pack once you can finish a few boards in a row without hints and it starts to feel easy. If a harder pack stops being fun, drop back. Nothing's lost by going back, and a relaxing Medium board after a long day is a perfectly good choice.

For a steady habit that doesn't depend on packs at all, a calm daily puzzle routine built around the two free daily boards works well. You can also warm up with today's free Linelet puzzle in your browser.

Questions people ask

How many boards does Linelet have?

862 boards in 21 packs. The first two packs, 50 boards in all, are free, and the rest open with a one-time $2.99 purchase. The two daily puzzles are free every day on top of that.

What sizes are the boards?

Pack boards run from 5x5 up to 13 across by 12 down. Most are square, and some are tall or wide, such as 7 across by 10 down or 10 across by 7 down. The biggest, 12x12 and 13x12, are in the Very hard packs.

Are bigger boards always harder?

Not always. Each board's label is measured against what's typical for a board of a similar size, so a tricky small board can be rated harder than a straightforward big one. Walls also tend to make a board easier, because they remove routes.

When should I move on to a harder pack?

Once you can finish a few boards in a row without hints and it starts to feel a little easy. If a harder pack stops being fun, drop back for a while. Nothing's lost by going back.