How to play Magnets

Decide which plates are magnets and which way round they go: like signs never touch, and the numbers count the + and − ends in each row and column. Also known as Magnet puzzle, Plus and minus plates.

▶ Play Magnets ⊞ Open the solver

The rules

The grid is covered by plates two squares long.
Each plate is either blank, or a magnet with one + end and one − end.
Two + ends never share a side, and neither do two − ends.
The numbers on the left and top say how many + ends each row and column has; those on the right and bottom count − ends.

Playing Magnets on Puzzle Solvers

Choose a size and a difficulty, then press New Puzzle.
Tap one end of a plate to make it + (the other end becomes −); tap again to swap, again for a blank plate, again to clear.
The Blank plate tool (or a right-click) marks plates that are not magnets.
Numbers on the left and top count + ends; numbers on the right and bottom count − ends. Hint explains the next deduction.

Open the Magnets game →

Using the Magnets solver

Choose the size, draw the plates and type the counts (or press Sample).
Press Solve and step through: lines with no + or − ends, plates forced by their neighbours, and line-by-line reasoning.

Open the solver →

A worked example

Row 1 shows 0 + ends and 0 − ends: every plate lying along row 1 is blank, and every plate sticking into it from row 2 is blank too.

A column of 6 needs 3 + and 3 − ends: all six squares are magnet ends, alternating where plates meet.

Strategies

Zeros. A row with no − ends can still hold + ends — but any plate lying along that row must be blank, because a magnet would put a − in it.
Pairs of numbers. If a row needs 3 + and 3 − ends in 6 squares, every square in it is a magnet end.
Opposites. A plate’s ends are always opposite. If one end is +, the other is −.
Neighbours. A + end makes the squares beside it (on other plates) either − or blank — never +.
Blank plates. When a line already has all its + and − ends, every other plate crossing it is blank there.

Common mistakes

Putting two + ends side by side on different plates.
Forgetting that a plate can be blank.
Mixing up which side counts + and which counts −.

Where it comes from

Magnet puzzles appear in many logic-puzzle collections and apps. They are a neat way to practise working with opposites and constraints.

Frequently asked questions

Can two + ends touch at a corner?

Yes — only squares sharing a side count as touching.

Is the plate layout always the same?

No — every puzzle has its own arrangement of plates.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

How do I solve one from a book?

Open the Magnets Solver, draw the plates, type the counts and press Solve.

Keep going

All guides: How to play every puzzle and game.