A short story, a few categories of items, and a grid of crosses and dots. Players work the numbered clues into the grid until every pairing is placed — and every clue set is proved to have exactly one answer, so it never comes down to guessing.
Name three to five categories, type their items, and pair them on the grid — one dot says which student, which project, which time slot go together. The clues are written for you and checked against your grid: every set is proved to have exactly one solution.
Your own words above the grid — who these people are and what happened. The solver never reads it, so it can be as playful as you like; the clues carry the logic.
Easy keeps to plain facts a player reads straight onto the grid. Medium adds either-or clues that need a second clue to settle. Hard adds two-way clues, exact distances along an ordered list, and the one deduction rule that only the toughest puzzles need.
A stuck player can ask for the next step. The grid places it and says which clue forces it — a lesson in the deduction, not a reveal. On by default; switch it off for a test.
Give the class a few minutes to close the grid. The run ends when the clock does, and the results say how far each player got.
Build the grid from your own world: which cousin brought which dish, which colleague sits at which desk, which pupil picked which project. Write the story, choose how hard it is and let the clues be written for you, or write them yourself — for a family party, a team day, a class or a puzzle hunt.
Four pupils, four projects, four time slots. Seven clues, one answer, worked out one cross at a time on the grid.
Five planets, their place from the Sun, what they are known for and the god they are named after. Every row is true: what pupils know fills the grid, three clues help with the rest.