PLANIGMA
Floor-Plan Mystery Puzzles
Volume One The Halmerton Case Files
Fifty murder mysteries you solve with a floor plan, a pencil and nothing else. Read the statements, work out where every guest was standing, and the room with the body will hold exactly one of them.
Get Volume One Try a case first
Paperback · 8.5″ × 11″ · full colour interior
How it works
Each guest says where they were — or, more often, where somebody else was not. Every statement is true.
One guest per row, one per column, never two in the same square. The statements rule out the rest.
When the plan is full, exactly one guest is standing in it. You have not guessed. You have proved it.
Try one now
Four guests, a four-by-four plan, four statements. One of these people is a murderer, and the statements are enough to say which.
Four guests to place
The statements
Mr Cole. The first statement pins his row and Miss Ashby’s. The second puts Lady Fenwick in the second row, first column — the top row is taken. Dr Hallam is the only one left who can be in the kitchen, which fixes his row, and because nobody else may be there, Miss Ashby takes the second column. The last statement decides the two remaining columns.
Of the 576 ways four guests can stand one to a row and one to a column, exactly one survives these four statements. Not the most likely one. The only one.
Why the seal is on the cover
Most puzzle books tell you there is one answer. This one has counted. Before a case is allowed into the book, a program lays out every legal arrangement of the guests on the plan and tests the statements against each one in turn.
The little case above has 576 arrangements. A full six-by-six case from the book has 518,400, of which 111,360 obey the rules of the board. If more than one of them survives the clues, the case is thrown away and never reaches you.
That is what the seal means. It is a measurement, not a promise.
The house party
You will get to know them over fifty cases — who is likely to be in the cellar at midnight, who never goes near the library. Four of them are found dead across the volume. The other ten have some explaining to do.
Volume one
Not sure yet? Download four cases free · Also available in Italian as I Casi di Halmerton House
Before you buy
A printable sample: four cases from volume one, from the gentlest to one that will hold you up, each with its full worked solution. Print it, sharpen a pencil, and see whether this is your kind of evening.
No more than that. You can leave whenever you like.