Puzzles that would be nice to add

• SET game puzzles

  • Find all sets
  • Find 20 cards with no set

• Sudoku including this

• Bitcoin mining

• NP-hard problems

  • Traveling salesman (solution uses simulated annealing)
  • https://en.wikipedia.org/wiki/Guillotine_problem (Mathematical Problems category)
  • SAT (in particular, random k-SAT)

• Matrix multiplication

  • Matrix inverse as the solution to matrix multiplication
  • Improvements on a Strassen-like matrix multiplication algorithm

• Compute Huffman codes using Garcia-Wachs algorithm

• Knights tour enumeration using OBDD

• Railroad rush hour, Sokhoban

• Erdos discrepency problem

• Stable marriage

• Stable roommates

• Pell's equation, find an integer solution to x^2 - n y^2 = 1

• Prouhet–Tarry–Escott problem

• Simple calculus maximizing a 1-d function

• Block stacking problem get creative!

• For the Boolean Pythangorean Triples puzzle we have, can we create a puzzle to address the open problem of Monochromatic Pythagorean Triples problem of coloring the triples with three colors? For example, can you design a puzzle which would prove that it is impossible by finding a subset of triples with a certain property?

• https://en.wikipedia.org/wiki/Disk_covering_problem (Mathematical Problems category)

• https://mathworld.wolfram.com/FiveDisksProblem.html

• https://en.wikipedia.org/wiki/Envy-free_cake-cutting (Mathematical Problems category)

• https://en.wikipedia.org/wiki/Firing_squad_synchronization_problem (Mathematical Problems category)

  • open problem: can you do it with 5 states?
  • See https://www.sciencedirect.com/science/article/pii/0304397587901241 for a 6-state solution
  • This is a hard problem in designing a cellular automaton, could be fun

• https://en.wikipedia.org/wiki/Hadwiger%E2%80%93Nelson_problem (Mathematical Problems category)

  • color the plane so no two unit-distance points have the same color, could be converted to a nice NP problem

• Find longest play in Conway's topswop game