Roboku
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Case 12: who took the Old Map?
The alarm at the library went off for no apparent reason for the third time this month, so almost no one paid attention. That was a mistake: this time the Old Map, kept in the Reading Room, really was missing. Help the police unmask the thief, who clearly knew exactly when no one checks the cameras.
The board
- 1Reading Room
- 2Storage Room
- 3Restoration Room
- 4Office
- 5Periodicals Room
- 6Vault
- 7Café
- 8Archive
- 9Children's Room
- 10Restrooms
- 11Reception Area
- Seat: anyone can be on it.
- Shelf: no character can stand on its cell, but the stolen item can be there.
- Screen: nothing can be on its cell.
- Window: the blue line on a wall.
Suspects and clues
- GGrace
She's in the Children's Room. - WWendy
She's in column E. - PPeter
He's next to a seat. - LLucy
She's in row 4. - BBilal
He's 3 columns away from the Periodicals Room. - IIvan
He's 5 rows away from the Reception Area. - OOld Map (stolen item)
It's next to a window.
Remember the rules: no two suspects (nor the item) ever share a row or a column, each character is in a different room, and the thief is the only one sharing a room with the stolen item. Unsure? Read how to play and the clue types.
Solution
Try it yourself first: pen and paper are enough. When you want to check, open the reasoned solution.
Show the step-by-step solution
- Grace's clue: She's in the Children's Room. 2 cells remain possible: B5 and B6.
- Wendy's clue: She's in column E. 6 cells remain possible: E1, E2, E3, E4, E5 and E6.
- Peter's clue: He's next to a seat. 3 cells remain possible: F5, G6 and F7.
- Lucy's clue: She's in row 4. 5 cells remain possible: A4, C4, D4, E4 and F4.
- Bilal's clue: He's 3 columns away from the Periodicals Room. It leaves a single cell: G3.
- Ivan's clue: He's 5 rows away from the Reception Area. 2 cells remain possible: B6 and C6.
- The stolen item's clue: It's next to a window. 4 cells remain possible: B1, D1, G1 and G6.
- Bilal can only be on G3. No one else can be in row 3 or column G, and no other character can be in the Archive.
- There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Wendy can still reach row 2, so that is where she must be.
- E1, E3, E4, E5 and E6 have already been ruled out, so Wendy can only be on E2. No one else can be in row 2 or column E, and no other character can be in the Periodicals Room.
- There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Peter can still reach row 7, so that is where he must be.
- F5 and G6 have already been ruled out, so Peter can only be on F7. No one else can be in row 7 or column F, and no other character can be in the Reading Room.
- There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Grace can still reach row 5, so that is where she must be.
- B6 has already been ruled out, so Grace can only be on B5. No one else can be in row 5 or column B, and no other character can be in the Children's Room.
- B6 has already been ruled out, so Ivan can only be on C6. No one else can be in row 6 or column C, and no other character can be in the Restrooms.
- B1, G1 and G6 have already been ruled out, so the Old Map can only be on D1. No one else can be in row 1 or column D.
- C4, D4, E4 and F4 have already been ruled out, so Lucy can only be on A4.
Conclusion: Wendy is the only person sharing the Periodicals Room with the Old Map, which is on D1. She is the thief.