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Comments in green were written by me. Comments in blue were not written by me.
2021-01-03
Happy New Year, one and all!
I think your links point to last year’s calendar puzzles. As for how to solve the puzzle on 21 December,
- permutations of [1,...,n+1] having no substring [k,k+1] - is an option.
(anonymous)
on
/blog/88
2021-01-03
@
(anonymous)
: Thanks, links corrected
Matthew
on
/blog/88
Archive
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A new puzzle every day
Mixing Wordle with other games
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Christmas (2025) is over
2025
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Christmas card 2025
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Christmas (2025) is coming!
Sep 2025
The partridge puzzle
Aug 2025
TMiP 2025 puzzle hunt
Jun 2025
A nonogram alphabet
Mar 2025
How to write a crossnumber
Jan 2025
Christmas (2024) is over
Friendly squares
2024
Dec 2024
A regular expression Christmas puzzle
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Christmas (2024) is coming!
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Zines, pt. 2
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Christmas (2023) is coming!
Zines
Sep 2023
TMiP 2023 puzzle hunt
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Chalkdust issue 17
Apr 2023
Logo Asteroids
Mar 2023
Mathsteroids on hyperbolic surfaces
Feb 2023
The databet
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Christmas (2022) is over
2022
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Dec 2022
Off-by-one errors
Christmas card 2022
Nov 2022
Christmas (2022) is coming!
Oct 2022
24 Hour Maths Game Show
Mar 2022
Approximating π
Feb 2022
Build your own MENACE
Jan 2022
Christmas (2021) is over
2021
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Dec 2021
Christmas card 2021
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May 2021
Close encounters of the second kind
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Christmas (2020) is over
2020
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Dec 2020
Christmas card 2020
Nov 2020
Christmas (2020) is coming!
Jul 2020
Happy -26+eg Approximation Day!
May 2020
A surprising fact about quadrilaterals
Interesting tautologies
Mar 2020
Log-scaled axes
Feb 2020
PhD thesis, chapter ∞
PhD thesis, chapter 5
PhD thesis, chapter 4
PhD thesis, chapter 3
Inverting a matrix
PhD thesis, chapter 2
Jan 2020
PhD thesis, chapter 1
Gaussian elimination
Matrix multiplication
Christmas (2019) is over
2019
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Dec 2019
Visualising MENACE's learning
Christmas card 2019
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Christmas (2019) is coming!
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A non-converging LaTeX document
TMiP 2019 treasure punt
Jul 2019
Big Internet Math-Off stickers 2019
Jun 2019
Proving a conjecture
Apr 2019
Harriss and other spirals
Mar 2019
realhats
Jan 2019
Christmas (2018) is over
2018
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Dec 2018
Christmas cross stitch
MENACE in fiction
Christmas card 2018
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Christmas (2018) is coming!
Sep 2018
Runge's Phenomenon
Jul 2018
World Cup stickers 2018, pt. 3
Mathsteroids
Jun 2018
World Cup stickers 2018, pt. 2
May 2018
A bad Puzzle for Today
Apr 2018
Building MENACEs for other games
Mar 2018
A 20,000-to-1 baby?
World Cup stickers 2018
Jan 2018
Origins of World War I
Christmas (2017) is over
2017
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Christmas (2017) is coming!
MENACE at Manchester Science Festival
Jun 2017
Big Ben Strikes Again
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The end of coins of constant width
Dragon curves II
Feb 2017
The importance of estimation error
Jan 2017
Is MEDUSA the new BODMAS?
2016
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Christmas (2016) is over
Video game surfaces
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Nov 2016
Christmas (2016) is coming!
Oct 2016
Logical contradictions
Palindromic dates
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Tube map kaleidocycles
Jul 2016
Solving the cross diagonal cover problem
Jun 2016
Braiding, pt. 2
Braiding, pt. 1
Making names in Life
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Euro 2016 stickers
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Proving Pythagoras' theorem
Dragon curves
The
Mathematical Games
of Martin Gardner
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Christmas (2015) is over
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Christmas (2015) is coming!
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How to kick a conversion
How much will I win on the new National Lottery?
Aug 2015
How OEISbot works
MENACE
Mar 2015
Optimal Pac-Man
Tube map stellated rhombicuboctahedron
Logic bot, pt. 2
Design your own flexagon
Jan 2015
Tube map Platonic solids, pt. 3
2014
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Logic bot
Sep 2014
Electromagnetic Field talk
Jun 2014
Tennis maths
May 2014
World Cup stickers
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Countdown probability, pt. 2
Countdown probability
Mar 2014
New machine unfriendly £1 coin, pt. 2
New machine unfriendly £1 coin
2013
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Dec 2013
Assorted christmaths
Pointless probability
Jul 2013
"Uncanny" royal coincidence
Raspberry Pi weather station
2012
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Nov 2012
Tube map Platonic solids, pt. 2
Oct 2012
Tube map Platonic solids
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Archive
Show me a random blog post
▼ show ▼
▲ hide ▲
2026
May 2026
World Cup stickers 2026
Apr 2026
A new puzzle every day
Mixing Wordle with other games
Feb 2026
Christmas (2025) is over
2025
Dec 2025
Christmas card 2025
Nov 2025
Christmas (2025) is coming!
Sep 2025
The partridge puzzle
Aug 2025
TMiP 2025 puzzle hunt
Jun 2025
A nonogram alphabet
Mar 2025
How to write a crossnumber
Jan 2025
Christmas (2024) is over
Friendly squares
2024
Dec 2024
A regular expression Christmas puzzle
Christmas card 2024
Nov 2024
Christmas (2024) is coming!
Feb 2024
Zines, pt. 2
Jan 2024
Christmas (2023) is over
2023
▼ show ▼
▲ hide ▲
Dec 2023
Christmas card 2023
Nov 2023
Christmas (2023) is coming!
Zines
Sep 2023
TMiP 2023 puzzle hunt
May 2023
Chalkdust issue 17
Apr 2023
Logo Asteroids
Mar 2023
Mathsteroids on hyperbolic surfaces
Feb 2023
The databet
Jan 2023
Christmas (2022) is over
2022
▼ show ▼
▲ hide ▲
Dec 2022
Off-by-one errors
Christmas card 2022
Nov 2022
Christmas (2022) is coming!
Oct 2022
24 Hour Maths Game Show
Mar 2022
Approximating π
Feb 2022
Build your own MENACE
Jan 2022
Christmas (2021) is over
2021
▼ show ▼
▲ hide ▲
Dec 2021
Christmas card 2021
Nov 2021
Christmas (2021) is coming!
Sep 2021
TMiP 2021 puzzle hunt
May 2021
Close encounters of the second kind
Jan 2021
Christmas (2020) is over
2020
▼ show ▼
▲ hide ▲
Dec 2020
Christmas card 2020
Nov 2020
Christmas (2020) is coming!
Jul 2020
Happy -26+eg Approximation Day!
May 2020
A surprising fact about quadrilaterals
Interesting tautologies
Mar 2020
Log-scaled axes
Feb 2020
PhD thesis, chapter ∞
PhD thesis, chapter 5
PhD thesis, chapter 4
PhD thesis, chapter 3
Inverting a matrix
PhD thesis, chapter 2
Jan 2020
PhD thesis, chapter 1
Gaussian elimination
Matrix multiplication
Christmas (2019) is over
2019
▼ show ▼
▲ hide ▲
Dec 2019
Visualising MENACE's learning
Christmas card 2019
Nov 2019
Christmas (2019) is coming!
Sep 2019
A non-converging LaTeX document
TMiP 2019 treasure punt
Jul 2019
Big Internet Math-Off stickers 2019
Jun 2019
Proving a conjecture
Apr 2019
Harriss and other spirals
Mar 2019
realhats
Jan 2019
Christmas (2018) is over
2018
▼ show ▼
▲ hide ▲
Dec 2018
Christmas cross stitch
MENACE in fiction
Christmas card 2018
Nov 2018
Christmas (2018) is coming!
Sep 2018
Runge's Phenomenon
Jul 2018
World Cup stickers 2018, pt. 3
Mathsteroids
Jun 2018
World Cup stickers 2018, pt. 2
May 2018
A bad Puzzle for Today
Apr 2018
Building MENACEs for other games
Mar 2018
A 20,000-to-1 baby?
World Cup stickers 2018
Jan 2018
Origins of World War I
Christmas (2017) is over
2017
▼ show ▼
▲ hide ▲
Dec 2017
Christmas card 2017
Nov 2017
Christmas (2017) is coming!
MENACE at Manchester Science Festival
Jun 2017
Big Ben Strikes Again
Mar 2017
The end of coins of constant width
Dragon curves II
Feb 2017
The importance of estimation error
Jan 2017
Is MEDUSA the new BODMAS?
2016
▼ show ▼
▲ hide ▲
Dec 2016
Christmas (2016) is over
Video game surfaces
Christmas card 2016
Nov 2016
Christmas (2016) is coming!
Oct 2016
Logical contradictions
Palindromic dates
Sep 2016
Tube map kaleidocycles
Jul 2016
Solving the cross diagonal cover problem
Jun 2016
Braiding, pt. 2
Braiding, pt. 1
Making names in Life
May 2016
Euro 2016 stickers
Mar 2016
Proving Pythagoras' theorem
Dragon curves
The
Mathematical Games
of Martin Gardner
Jan 2016
Christmas (2015) is over
2015
▼ show ▼
▲ hide ▲
Nov 2015
Christmas (2015) is coming!
Oct 2015
How to kick a conversion
How much will I win on the new National Lottery?
Aug 2015
How OEISbot works
MENACE
Mar 2015
Optimal Pac-Man
Tube map stellated rhombicuboctahedron
Logic bot, pt. 2
Design your own flexagon
Jan 2015
Tube map Platonic solids, pt. 3
2014
▼ show ▼
▲ hide ▲
Nov 2014
Logic bot
Sep 2014
Electromagnetic Field talk
Jun 2014
Tennis maths
May 2014
World Cup stickers
Apr 2014
Countdown probability, pt. 2
Countdown probability
Mar 2014
New machine unfriendly £1 coin, pt. 2
New machine unfriendly £1 coin
2013
▼ show ▼
▲ hide ▲
Dec 2013
Assorted christmaths
Pointless probability
Jul 2013
"Uncanny" royal coincidence
Raspberry Pi weather station
2012
▼ show ▼
▲ hide ▲
Nov 2012
Tube map Platonic solids, pt. 2
Oct 2012
Tube map Platonic solids
Tags
advent calendar
logs
mathslogicbot
matrices
chalkdust magazine
interpolation
computational complexity
dragon curves
reddit
logic
game show probability
binary
a gamut of games
cambridge
coins
manchester
sobolev spaces
alphabets
royal baby
crossnumber
bubble bobble
plastic ratio
gerry anderson
folding paper
dataset
numbers
crosswords
estimation
electromagnetic field
friendly squares
newcastle
platonic solids
talking maths in public
mean
weather station
palindromes
graphs
national lottery
regular expressions
misleading statistics
wool
royal institution
countdown
machine learning
graph theory
live stream
radio 4
geogebra
programming
martin gardner
php
matt parker
football
triangles
sport
golden ratio
mathsteroids
exponential growth
harriss spiral
london underground
light
the aperiodical
finite group
go
pac-man
bempp
gaussian elimination
frobel
captain scarlet
tennis
signorini conditions
numerical analysis
wave scattering
nine men's morris
latex
data visualisation
folding tube maps
propositional calculus
thirteen
pi
cross stitch
fractals
hats
craft
crochet
warwick
world cup
fence posts
hexapawn
edinburgh
tmip
rust
coventry
matrix of cofactors
ternary
preconditioning
rugby
bluesky
chess
finite element method
correlation
guest posts
kenilworth
gather town
nonograms
tetris
menace
curvature
python
dates
oeis
pizza cutting
puzzles
stickers
convergence
matrix of minors
determinants
databet
runge's phenomenon
inline code
pi approximation day
dinosaurs
crossnumbers
zines
matrix multiplication
accuracy
statistics
draughts
wordle
simultaneous equations
european cup
24 hour maths
people maths
stirling numbers
probability
raspberry pi
quadrilaterals
asteroids
rhombicuboctahedron
standard deviation
arithmetic
braiding
realhats
arrangement puzzles
video games
partridge puzzle
errors
data
reuleaux polygons
bots
approximation
big internet math-off
weak imposition
news
ucl
game of life
london
anscombe's quartet
christmas
turtles
pascal's triangle
polynomials
hannah fry
sorting
bodmas
squares
golden spiral
javascript
christmas card
kings
flexagons
inverse matrices
hyperbolic surfaces
final fantasy
youtube
datasaurus dozen
sound
pokémon
books
games
chebyshev
pokémon wordle
recursion
trigonometry
mathsjam
noughts and crosses
map projections
logo
error bars
phd
manchester science festival
boundary element methods
speed
pythagoras
fonts
geometry
© Matthew Scroggs 2012–2026
I think your links point to last year’s calendar puzzles. As for how to solve the puzzle on 21 December, - permutations of [1,...,n+1] having no substring [k,k+1] - is an option.
on /blog/88