freefun.
The puzzle notebook

Learn the move.
See the reason.

Practical lessons with specific positions to work through. Start with a familiar game or explore a different way of thinking.

01Tile Shift

Stop chasing tiles. Start thinking in loops.

Use the empty square as a tool, and move a group of tiles without undoing the whole board.

5 min read · Worked examples02Number Merge

In Number Merge, read the board after the move.

Learn to predict a slide, avoid double-counting merges, and keep space for the next tile.

5 min read · Worked examples03Memory Match

Give every memory card an address.

Replace vague impressions with a simple row-and-column map, and get useful information from a mismatch.

4 min read · Worked examples04Light Switch

Light Switch: move the problem down the board.

Use row-by-row light chasing to make a complicated grid easier to reason about.

5 min read · Worked examples05Line Three

Line Three: look for threats before opportunities.

A practical order for reading a tic-tac-toe board: win, block, then investigate forks.

5 min read · Worked examples06Sum Select

Find the missing piece of a sum.

Use remainders and small adjustments to find a target without checking every combination.

4 min read · Worked examples07Getting started

Choose a puzzle that fits the break you have.

Match a game to your available attention, control preferences, and appetite for a longer problem.

4 min read · Worked examples08Behind the board

How we make a puzzle solvable before you start.

Three construction methods explain why a shuffled board can be a fair challenge instead of an impossible one.

5 min read · Worked examples