Magnets Solver

Magnets Solver — Step by Step

Drag across two squares to make each plate, click each count outside the grid and type it, then press Solve. Or play a generated puzzle and send it here with one click.

Magnets Solver: rules, how to use it, tips

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.

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.

Using the 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.

Tips

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 +.

The full guide, with a worked example and common mistakes: How to play Magnets.

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.