Magnet Dominoes Unblocked

Magnet Dominoes starts with a grid of grey domino outlines and asks a surprisingly physical question: which of these pieces are magnetic, and how is each one oriented? Magnets carry one positive and one negative pole. Blanks carry none. Numbers around the edge tell you how many of each pole sit in every row and column, and identical poles are never allowed to be neighbors. Known as Magnets in Simon Tatham’s puzzle collection, where James Harvey contributed it, the game runs unblocked on FreezeNova and never needs a guess.

Poles, Blanks and Edge Numbers

Each domino covers two squares, and the layout is fixed from the start. Your job is only to label them.

• A magnet gives one half a positive pole and the other half a negative pole.
• A blank leaves both squares neutral.

Clues along the upper and left borders, flagged with a plus sign, give the number of positive poles in each column and row. Clues along the lower and right borders, flagged with a minus, do the same for negative poles. On the strip-clue settings some numbers are missing.

The one extra rule: matching poles cannot be orthogonal neighbors. Two pluses may not share a side, and neither may two minuses. Corner contact is fine, and neutral halves can sit beside any pole.

A click turns a domino into a magnet, with its positive end on the half under your pointer. A second click reverses it and a third removes it. Right-clicking labels it blank instead. The grid flashes when everything is right. Preset boards come in three sizes, from 6x5 up to 10x9, at Easy or Tricky.

Magnet Dominoes controls

To do this	Keyboard	Mouse	Touch
Lay a magnet, flip it, then clear it	Arrow keys to move, then Enter (repeat to cycle)	Left-click a domino (repeat to cycle)	Tap a domino with Tap set to Magnet
Mark blank, then "not blank", then clear	Space (repeat to cycle)	Right-click a domino (repeat to cycle)	Press and hold, or set Tap to Blank domino and tap
Dim a clue you have satisfied	—	Click the clue	Tap the clue
New puzzle, undo, redo	N, U, R	Menu buttons above the grid	Menu buttons above the grid

Working Through a Grid

Here is a rough order that handles most boards.

1. Add up each row’s two clues. If plus plus minus equals the row length, there are no blanks in that row at all. If it is zero, every domino touching that row must be blank.
2. Use zeros on one pole. A row with 0 plus poles can still have minus ends and neutral ends. Any domino lying flat in that row must be blank, because a flat magnet would add a plus.
3. Think about orientation. A horizontal magnet contributes both a positive and a negative to its row. A vertical magnet adds only one pole to each of the two rows it spans. When a row’s plus and minus clues differ, vertical magnets must make up the gap.
4. Spread out from each magnet you place. Its plus end rules out a plus on every neighboring square, and its minus end rules out a minus. That often forces the next domino’s direction.
5. Note what you know. Mark dominoes you have proven are magnets with question marks while their direction is still open, and dim any clue whose count is already reached.

Who Will Like It

It suits anyone who enjoys number-edge puzzles but wants rules a little different from the usual. Easy 6x5 boards take a few minutes, and Tricky 10x9 boards can fill a lunch break. For more domino logic, try Dominosa Domino Logic, or browse the full list of puzzle games.