Ponder This

Welcome to our monthly puzzles.
You are cordially invited to match wits with some of the best minds in IBM Research.

Seems some of us can't see a problem without wanting to take a crack at solving it. Does that sound like you?

Good. Forge ahead and ponder this month's problem. We'll post a new one every month, and allow a month for you to submit solutions (we may even publish submitted answers, especially if they're correct).

And now... here's our
Jan. 2022 challenge!

Here is the solution for our Dec. 2021 problem

We usually won't reply individually to submitted solutions but every few days we will update a list of people who answered correctly. At the beginning of the next month, we'll post the answer.

So give your mind a break from its routine---you never know what other problems you may solve in the process!


Hosted by
IBM Research - Haifa

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The current puzzlemaster of Ponder This is Gadi Aleksandrowicz. Previous puzzlemasters include Oded Margalit (2007-2020), James Shearer (2005-2009), and Don Coppersmith (1998-2005).


Ponder This Top 52 SolversList Updated: May 24th 2020

Solver Challenges solved
Daniel Bitin 138
Dan Dima 134
Joseph DeVincentis 113
Clive Tong 96
David Greer 95
Radu-Alexandru Todor 88
David Friedman 88
Liubing Yu 84
Motty Porat 81
Harald Bögeholz 79
Andreas Stiller 78
Todd Will 77
Nyles Heise 73
Florian Fischer 69
Albert Stadler 69
James Dow Allen 69
John Tromp 68
Peter Gerritson 65
Chris Shannon 65
Tamir Ganor 63
Chuck Carroll 63
Amos Guler 63
Mathias Schenker 61
Kang Jin Cho 58
Lorenz Reichel 58
Armin Krauss 58
Solver Challenges solved
Reiner Martin 58
Shirish Chinchalkar 57
Daniel Chong Jyh Tar 56
Michael Brand 56
Shouky Dan 55
John G. Fletcher 53
Stéphane Higueret 52
Alex Fleischer 51
Luke Pebody 51
Dieter Beckerle 48
John T. Robinson 48
Graham Hemsley 47
Arthur Breitman 47
Adam Daire 45
Bert Dobbelaere 44
Gale Greenlee 44
Victor Chang 44
Christian Blatter 43
Alan Murray 43
Francis Golding 43
Jan Fricke 42
Phil Muhm 42
Oleg Vlasii 41
Hugo Pfoertner 40
Arthur Vause 40
Aviv Nisgav 40