Puzzles and riddles
I have a certain interest in puzzles and riddles.
For this reason, it is not strange that it is on of these
reoccuring subject in my online diary.
Squares on a grid
(proven to be NP-complete for sufficient
colors and size.)
- December 6, 2002
- February 19, 2003: Wang Tiles
- February 19, 2003: Wang Tiles
- September 2, 2003: Program
- September 3, 2003
- August 7, 2007
- August 24, 2007: 140 unsolved
- August 25, 2007: 132 unsolved
- September 16, 2007: 14 unsolved?
- September 23, 2007: 10 unsolved?
- October 26, 2007: 10 unsolved!
- May 12, 2008: Bug found in program
- May 13, 2008: Large setback
- Havannah on MindSports
- Havannah on Wikipedia
- Formalization
- Formalisation of abstract games
- March 9, 2003: Improved formalization
- January 5, 2005: Playing
- March 21, 2009: Meeting Christian Freeling
- July 11, 2011: Monte-Carlo Tree Search
- July 13, 2010: The Symple challange
- July 17, 2011: MCTS and Symple
- July 18, 2011: Fuego
- July 23, 2011: Strongest human player
- August 3, 2011: Castro, strongest program
- August 7, 2011: More Havannah bots
- December 29, 2011: Playing and solving Havannah
- June 2, 2012: Playing some games
- September 14, 2012: Havannah Challenge 2012
- October 16, 2012: Christian defeated during challenge
- October 19, 2012: Havannah Challenge: 7 - 3
- July 18, 2015: Havannah versus Hex
- July 29, 2015: Havannah versus Hex (part 2)
- August 13, 2015: Havannah versus Hex (part 3)
- March 8, 2003
- December 28, 2003
- December 27, 2005: Counter example
- December 31, 2005: Smallest 'hard' Nonogram
- January 3, 2006: Large nonogram
- January 13, 2006
- February 14, 2006
- February 16, 2006
- February 27, 2006
- February 28, 2006
- March 1, 2006
- March 2, 2006
- March 3, 2006
- March 13, 2006
- April 4, 2006
- April 5, 2006
- April 11, 2006
- April 22, 2006: NP-completeness
- January 22, 2007: Exact cover
- June 13, 2009: Exact Covers of nonograms
- June 27, 2009: Exact Covers of nonograms
- June 28, 2009: Exact Covers of nonograms
- August 18, 2009
- August 23, 2009
- February 18, 2010: Survery of solvers
- August 15, 2010: Knot Nonogram
- August 17, 2010: Knot Nonogram (Part 2)
- September 8, 2010: Knot Nonogram (Part 3)
- January 20, 2011: Polynomial algorithm for 3-Sat
- March 7, 2013: Alphabet Cover
- September 25, 2013: Large nonogram
- September 2, 2003: Square grids
- September 3, 2003: Extending "backwards" possible?
- November 8, 2003: Extending "backwards" possible!
- November 9, 2003: Repeating Rule 30 patterns
- January 9, 2005: Repeating Rule 30 patterns
- December 18, 2005: Rule 30 jigsaw
- December 30, 2006: More Rule 30 Jigsaws
- August 7, 2007: Rule 30 square tiling?
- August 7, 2007: Mapping cellular automata to tilings
- September 23, 2019: Displaying repeating patterns
See also:
- March 5, 2005: Latin Square algorithm
- March 8, 2005: Idea for Exact Cover algorithm
- April 24, 2005: Implementation
- April 25, 2005: Exact Cover algorithm solves Latin Square
- January 13, 2006: Solving the nonogram
- January 22, 2007: Nonogram to Exact Cover
- January 23, 2007: Solving an Exact Cover
- January 27, 2007: Exact Cover Reducer
- January 28, 2007: Smallest 'hard' Exact Cover with one solution
- February 9, 2007: Smallest 'hard' Exact Cover with one solution
- May 12, 2009: Simple, but powerful heuristic
- May 17, 2009: Trivial, but powerful heuristic
- May 20, 2009: Beat the Computer No. 24
- June 13, 2009: Exact Covers of nonograms
- June 27, 2009: Exact Covers of nonograms
- June 28, 2009: Exact Covers of nonograms
- July 19, 2009: Generalization of reduction
- July 28, 2009: Exact Cover and ZDD
- April 23, 2010: Difficult Exact Cover problems
- April 24, 2010: Difficult Exact Cover problems
- April 28, 2010: P versus NP
- May 24, 2010: XHS paper
- May 26, 2010: Single Solution Exact Cover
- June 28, 2010: Infinite grid coverings
- September 9, 2010: Hardest Sudoku
- March 17, 2011: Proof
- October 10, 2011: Binary Puzzles
- March 7, 2013: Alpabeth Cover
- October 27, 2017: HEMA puzzle
- February 10, 2017: The MacMahon Squares
- March 20, 2019: Estimating
- June 24, 2019: Complexity
- June 17, 2020: Suguru puzzles
- August 2. 2020: Round Goki puzzle
- December 5, 2020: Hyper Sudoku
- December 12, 2020: Futoshiki to Exact Cover
- December 28, 2020: Goki puzzle: no touching colours
- April 19, 2021: Hexagon puzzel
- September 18, 2023: Estimating
- November 7, 2024: Cubes from Sheet: 11 by 11
- July 29, 2006: Introduction
- September 5, 2006: To the office
- November 9, 2006: Small Chinese Wooden Puzzle
- December 25, 2006: One six piece solution
- December 27, 2006: 3 by 10 solutions
- December 28, 2006: 5 by 6 solutions
- January 9, 2007: No pieces same colour touching
- January 13, 2007: C++ program
- January 14, 2007: More solutions
- January 16, 2007: Solutions for a hard case
- March 11, 2007: Titus finds a solution
- November 30, 2007: Error in program?
- December 2, 2007: Program seems correct
- December 6, 2007: Program is correct
- December 8, 2007: Vertical division line
- February 21. 2007: 9 by 7 solutions
- February 22, 2008: Least connected
- October 4, 2009: Compact solutions
- October 5, 2009: 15 by 4 solutions
- May 22, 2013: Solutions for a hard case
- May 25, 2013: White, orange, green and black
- May 27, 2013: White, orange, red, and black or green
- June 28, 2013: 8 by 10 solutions
- July 20, 2013: Sold by Dille & Kamille
- November 18, 2015: White, orange, yellow, and red
- December 23, 2015: Corrected 8 by 10 solutions
- December 23, 2015: Corrected or verified all 8 by 10 solutions
- January 16, 2016: Minimal touching
- February 7, 2016: Minimal touching
- December 6, 2016: Additional condition
- December 7, 2016: Six solutions
- December 9, 2016: More solutions
- April 9, 2017: Horizontal division line
Latest PostScript file.
- April 28, 2010: Introduction
- May 20, 2010: Boolloop language
- May 24, 2010: XHS paper
- May 26, 2010: Single Solution Exact Cover
- May 27, 2010: Scott Aaronson
- June 3, 2010: Informal introduction to the status of the problem
- August 9, 2010: NP is not P
- September 12, 2010: P versus NP still unresolved
- January 20, 2011: Polynomial algorithm for 3-Sat
- February 28, 2011: Shortcoming in Sat-3 algorithm
- March 17, 2011: Proof
- March 30, 2011: Natural Proofs
- September 25, 2013: Intro
- September 26, 2013: JavaScript
- September 30, 2013: Catalan numbers
- October 12, 2013: Mathematical Vistas
- October 23, 2013: Sequence A056353
- October 25, 2013: Two more sequences
- October 27, 2013: Even more sequences
- October 28, 2013: Transition graph
- November 23, 2013: Proof idea
- December 1, 2013: Reductions
- December 2, 2013: Euler characteristic
- December 2, 2013: plantri
- December 4, 2013: Hexagon and double pentagon chain
- December 6, 2013: Doubling
- December 8, 2013: Partial doubling
- December 11, 2013: Simplest doubling
- December 16, 2013: Solid proof
- July 15, 2014: Two tree graphs
- July 24, 2013: 4-connected
- July 26, 2014: Another dead-end
- July 29, 2014: Triangulation of regular polygons
- May 5, 2015: Six pentagons
- May 8, 2015: Cycles in transition graph
- May 18, 2015: Proof with Kempe chains?
- May 19, 2015: Working out the details
- May 21, 2015: Old Kempe proof after all?
- June 25, 2015: 'Volume' of planar graph
- July 13, 2015: 'Volume' of icosahedron
- February 16, 2016: Predicting number of solutions
- April 20, 2016: Hexagons
- January 8, 2018: Edge marking
- August 26, 2015: Introduction
- September 3, 2015: Slicing method
- September 12, 2015: 2 by 2 unique configurations
- September 16, 2015: Corrections
- September 26, 2015: Unique configurations
- September 30, 2015: Maximal number of connections
- October 6, 2015: Maximal number of connections (part 2)
- August 11, 2019: KABK wrapping paper
- August 30, 2020: PARR generator
- September 20, 2020: PARR specification
- October 25, 2020: PARR books
- Results
- March 4, 2016: Introduction
- March 8, 2016
- April 10, 2016
- April 16, 2016: Sequences
- May 1, 2016: Wang tiles
- May 10, 2016: Versaille pattern
- May 14, 2016: Diagonal sequences
- May 20, 2016: Diagonal sequences corrected
- June 5, 2016: Corrected again
- June 13, 2016: More Versaille like patterns
- January 15, 2017: Animation for BYOB
- November 1, 2017: Turing complete?
- November 12, 2017: Infinite sequences
- December 17, 2017: Grammar
- December 19, 2017: 89 states
- December 20, 2017: More is needed
- December 27, 2017: Random
- January 3, 2018: More random
- January 4, 2018: Fix for random
- June 24, 2018: 8 by 8 with fixed palette
- July 3, 2022: Applied in back garden
- July 9, 2022: Versaille pattern
- December 24, 2022: Theo van Doesburg
- October 30, 2016: Introduction
- November 1, 2016: SVG experiment
- December 11, 2016: Combined program
- December 27, 2016: WinterGo
- January 14, 2016: Bottom generation
- November 3, 2017: 3D version
- August 26, 2018: Fixed and improved program
- September 2, 2018: Added -space option
- June 17, 2019: Puzzles by Annabel
- June 24, 2019: Complexity
- June 25, 2019: Hardest
- July 3, 2019: Difficulty versus number of solutions
- June 15, 2017: Introduction
- June 21, 2017: Smallest maximum
- June 29, 2017: Necklage
- August 14, 2017: Proof
- August 19, 2017: Solutions for 7 and 8
- September 22, 2017: Solutions for 9
- September 28, 2017: 105869 solutions
- September 29, 2017: 885 solutions for 10 with 22 integers
- October 5, 2017: Proof for conjecture
- March 5, 2018: More solutions for 7
- March 6, 2018: More solutions for 8
- April 5, 2018: 5 solutions for 9 with 19 integers
- April 10, 2018: No solutions for 10 with 21 integers
- May 1, 2018: 428,362 sets of equations
- July 3, 2018: 33.35%
- August 20, 2018: Existence proof
- August 22, 2018: Lower bound
- August 24, 2018: Proof?
- November 10, 2018: 469410 solutions
- February 13, 2019: Intro
- February 14, 2019: Exact Cover to SAT
- February 19, 2019: 4x4
- March 15, 2019: The China Labyrith
- March 16, 2019: Solutions
- March 20, 2019: Estimating
- September 18, 2023: Estimating
- September 25, 2023: Analyzing solutions
- October 3, 2023: OctoPuszle: 6×6 groups
- October 8, 2023: OctoPuszle progress report
- April 3, 2022: Introduction
- April 4, 2022: Dodecagon
- April 6, 2022: Regular example
- April 9, 2022: More irregular grids
- April 13, 2022: Even more irregular grids
- May 1, 2022: Generation method
- July 11, 2022: Finding unique patterns
- Sunday, August 14, 2022: Visualization
- Thursday, August 18, 2022: Unique patterns
- Thursday, August 23, 2022: Irregular grids
- Sunday, October 16, 2022: Grid Index
- Sunday, October 23, 2022: gi-dt-005
- Sunday, November 20, 2022: Infinite
- Wednesday, December 7, 2022: Subsitution patterns
- Saturday, December 10, 2022: All combinations
- Wednesday, December 14, 2022: Elementary triangle
- Sunday, December 18, 2022: Alternative couplings
- Tuesday, January 3, 2023: Boundary of subsitution patterns
- Sunday, January 8, 2023: Substitution patterns
- Sunday, January 22, 2023: Small area substitution patterns
- Monday, July 10, 2023: Watanabe Ito Soma 12-fold
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