16 Puzzles for International Puzzle Day
January 29, 2008 — Ed Pegg Jr, Editor, Wolfram Demonstrations Project
Today (Tuesday, January 29) is International Puzzle Day. To celebrate, here are 16 puzzles from the Wolfram Demonstrations Project.
|1. Box Packing
||2. Dissection Fallacy
|Can 27 3×4×5 blocks be placed in a 12×12×12 box? How about 27 a×b×c blocks?
||Four identical shapes have an area of 64 or 65, depending on their arrangement. How?
|3. Box Toppling Patterns
||4. Four-Color Maps
|A box gets rolled around on a floor. After 5 topples, how many different places can it be?
||What is the connection between borders and map coloring?
|5. Shortest Time Problem
||6. Loculus of Archimedes
|A tennis ball is thrown in a lake. What route allows the ball to be retrieved in the shortest time?
||If a square is divided into the above shapes, how many different ways can the square be made?
|7. Number of Squares in a Square
||8. Measuring the Speed of Light
|How many squares are in this grid of squares?
||You have a bag of marshmallows and a microwave. How can you measure the speed of light?
|9. The Statue of Regiomontanus
||10. Orchard-Planting Problem
|Where should you stand so that a statue appears to be as large as possible?
||Can 10 trees be arranged so that there are 5 rows, each containing 4 trees?
|11. Eight Queens Puzzle
||12. Guilloché Patterns
|How many ways can 8 queens be placed on a chessboard so that none attack each other?
||What are the rules for the strange curves found on paper currency?
|13. Lights Out Puzzle
||14. Urn Problem
|Click on a square to change neighboring lights. How can all the lights be turned off?
||An urn holds 7 good balls, and 20 bad balls. If 5 balls are chosen, what are the odds that 2 will be good?
|15. The Circle Covering Puzzle
||16. Haberdasher’s Problem
|Can you completely cover the orange shape with the given set of disks?
||Can a square be cut into 4 pieces and rearranged into an equilateral triangle?