Old Tricks, New Moves
Familiar puzzles. A fresh way to play.
Four classic ideas, rebuilt as little experiments. Try a move, watch what changes, and work out why it works.
Choose a puzzle
Completed puzzles stay in this browser. No account or timer.
Where these puzzles come from
Puzzle roots & our approach
- Fox search: Rustan Leino’s puzzle collection (credits Claude Marché for a related form).
- River crossing: MacTutor on Alcuin’s puzzle book (a historical account of the river puzzle).
- Tower of Hanoi: MacTutor history of Édouard Lucas (Lucas, 1883).
- Queens: V. Chvátal’s eight queens history (first posed by Bezzel in 1848).
We adapted only the puzzle mechanics. The teaching text, visuals and code on this page were made for Qidolab; these links document earlier forms of the ideas.