IBM Research | Ponder This | October 2013 challenges

# Ponder This

## October 2013

<<September October November>>

Ponder This Challenge:

Color the squares of an 8x8 check-board in two colors (black and white) and calculate the percentage of black squares in every one of the 8 rows, 8 columns and 30 diagonals.

Our challenge this month is to find such coloring which gives the same percentage for every row; different one for every column and as many different numbers in the diagonals as possible.

For example, the following is a solution for a 2x2 case of the problem:
BW
BW

The column percentage is 0%, 100%; all rows are 50% and the diagonals has 0%,50% and 100% (each appears twice).

We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!

We invite visitors to our website to submit an elegant solution. Send your submission to the ponder@il.ibm.com.

If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com

Challenge: 10/01/2013 @ 01:00 PM EST
Solution: 11/01/2013 @ 01:00 PM EST
List Updated: 10/18/2013 @ 01:00 PM EST

Lorenz Reichel (10/02/2013 05:04 AM EDT)
Tatiana Stepanova (10/02/2013 04:52 AM EDT)
Andrew Gacek (10/02/2013 10:43 AM EDT)
Don Dodson & David Dodson (10/02/2013 11:17 AM EDT)
Andreas Razen & Radu-Alexandru Todor (10/02/2013 11:44 AM EDT)
Jason Patskoski (10/02/2013 11:54 AM EDT)
Joseph DeVincentis (10/02/2013 01:53 PM EDT)
Dan Dima (10/02/2013 02:12 PM EDT)
Alan Murray (10/02/2013 03:12 PM EDT)
Alex Wagner (10/02/2013 03:29 PM EDT)
Joe Clark (10/02/2013 04:14 PM EDT)
Alex Fleischer (10/02/2013 04:34 PM EDT)
Cynthia Beauchemin (10/02/2013 08:45 PM EDT)
Kan Shen (10/02/2013 09:23 PM EDT)
Leandro Araújo (10/02/2013 09:33 PM EDT)
Antoine Comeau (10/03/2013 12:34 AM EDT)
Liubing Yu (10/03/2013 01:37 AM EDT)
Dheeraj Reddy (10/03/2013 01:57 AM EDT)
Kurt Hectic (10/03/2013 05:22 AM EDT)
James Dow Allen (10/03/2013 06:35 AM EDT)
Tatiana Stepanova (10/03/2013 07:09 AM EDT)
Tim Nordenfur (10/03/2013 10:16 AM EDT)
Michael Wilms (10/03/2013 01:34 PM EDT)
Adam Kozdron (10/03/2013 02:22 PM EDT)
Aleksei Galak (10/03/2013 04:13 PM EDT)
I. J. Kennedy (10/03/2013 05:36 PM EDT)
Dieter Beckerle (10/04/2013 02:46 AM EDT)
Todd Will (10/04/2013 11:57 AM EDT)
Tom Harley (10/04/2013 12:18 PM EDT)
Philipp Seemann (10/04/2013 12:50 PM EDT)
Mark Pervovskiy (10/04/2013 02:24 PM EDT)
Michael Gurvich & Chintan Maggu (10/04/2013 10:52 PM EDT)
Florian Fischer (10/05/2013 02:06 PM EDT)
Shirish C (10/05/2013 07:46 PM EDT)
José Eduardo Gaboardi de Carvalho (10/05/2013 08:36 PM EDT)
Dezhi Zhao (10/05/2013 11:01 PM EDT)
Dustin Shively (10/05/2013 11:56 PM EDT)
Rob Sessions (10/06/2013 12:09 AM EDT)
Harald Bögeholz (10/06/2013 06:19 AM EDT)
Nicholas Ngiam & Liu Ren Wei (10/06/2013 11:31 AM EDT)
Mark Kattenbelt (10/06/2013 02:25 PM EDT)
Eugene Lee (10/06/2013 02:30 PM EDT)
Hakan Kjellerstrand (10/07/2013 02:26 AM EDT)
Hakan Summakoglu (10/07/2013 01:50 PM EDT)
Chuck Carroll (10/07/2013 03:08 PM EDT)
Adib Surani (10/07/2013 06:16 PM EDT)
Joseph Berman
(10/07/2013 07:42 PM EDT)
Yiqian Lu
(10/07/2013 08:32 PM EDT)
Alexei Kopylov
(10/07/2013 08:42 PM EDT)
(10/07/2013 11:49 PM EDT)
Rogerio Ponce da Silva
(10/07/2013 06:18 PM EDT)
Amos Guler
(10/08/2013 07:07 AM EDT)
Matthew Charlap
(10/08/2013 07:54 AM EDT)
David Friedman
(10/08/2013 11:34 AM EDT)
Robin Ryder
(10/08/2013 12:32 PM EDT)
Aharon Malachi
(10/08/2013 12:53 PM EDT)
Hubert Kahlert
(10/08/2013 01:53 PM EDT)
Balakrishnan Varadarajan (10/08/2013 03:10 PM EDT)
Olivier Mercier (10/08/2013 02:58 PM EDT)
Julien Briton (10/09/2013 03:24 AM EDT)
Yasodhar (Pattu) Patnaik (10/08/2013 09:32 PM EDT)
Umut Uludag (10/09/2013 08:56 AM EDT)
Fletcher Dostie (10/09/2013 12:26 PM EDT)
David Greer (10/09/2013 12:56 PM EDT)
Vivek Viswanathan (10/09/2013 01:10 PM EDT)
Andrei Prudius & Satish Vedantam (10/09/2013 04:13 PM EDT)
Clive Tong (10/10/2013 01:08 AM EDT)
Shouky Dan & Tamir Ganor (10/10/2013 04:13 AM EDT)
Steffen Suerbier (10/10/2013 10:01 AM EDT)
Mathias Schenker (10/10/2013 11:01 AM EDT)
Serafim Chekalkin (10/10/2013 11:46 AM EDT)
Ivan Bendyna (10/10/2013 03:07 PM EDT)
Mukund R (10/10/2013 11:31 PM EDT)
Maris Van Sprang (10/11/2013 02:03 AM EDT)
Guangda Huzhang (10/11/2013 03:27 AM EDT)
Pål Hermunn Johansen (10/11/2013 05:13 AM EDT)
Berend Jan van der Zwaag (10/11/2013 09:43 AM EDT)
Daniel Bitin (10/12/2013 03:39 PM EDT)
Andrea Andenna (10/12/2013 05:28 PM EDT)
Anatoli Plotnikov (10/13/2013 02:42 AM EDT)
Klaus Nagel (10/13/2013 03:13 AM EDT)
Armin Krauss (10/13/2013 09:39 AM EDT)
Ken Meehan (10/13/2013 11:44 AM EDT)
Marcel Caria (10/15/2013 09:18 AM EDT)
Evert van Dijken (10/15/2013 09:45 AM EDT)
Peter Gerritson (10/15/2013 10:22 AM EDT)
Igor Novak (10/15/2013 11:16 AM EDT)
Tao Liu (10/15/2013 01:57 PM EDT)que
Alok Menghrajani (10/15/2013 04:57 PM EDT)
Christian Pape (10/16/2013 05:58 AM EDT)
John Tromp (10/16/2013 04:19 PM EDT)
Frank Methling (10/17/2013 11:01 AM EDT)
William Heller (10/19/2013 02:59 PM EDT)
Dennie Tyshchenko (10/20/2013 03:17 PM EDT)
Motty Porat (10/20/2013 04:24 PM EDT)
Adrian Orzepowski (10/21/2013 11:47 PM EDT)
Dan Cervone (10/22/2013 11:30 AM EDT)
Derek Kisman (10/22/2013 04:34 PM EDT)
Hugues Juille (10/23/2013 03:40 PM EDT)
Thomas Egense (10/25/2013 12:21 AM EDT)
Scott Abbey (10/25/2013 01:23 AM EDT)
Gilad Weiss (10/25/2013 10:16 AM EDT)
Antonio García Astudillo (10/25/2013 11:49 AM EDT)
Minxi Jiang (10/26/2013 09:42 AM EDT)
Rob Pratt (10/26/2013 11:07 AM EDT)
David Chang (10/26/2013 11:34 PM EDT)
Alessandro Silva (10/27/2013 11:27 AM EDT)
Boris Rakus (10/28/2013 06:18 AM EDT)
Yaniv Meoded (10/28/2013 08:15 AM EDT)
Stéphane Higueret (10/28/2013 11:27 AM EDT)
Greg Bubnis (10/29/2013 01:20 AM EDT)
Tilmann Steinberg (10/29/2013 11:17 AM EDT)
Alkeos Tsokos (10/29/2013 12:45 PM EDT)
David Vainapel (10/29/2013 03:26 PM EDT)
Maithem Munshed (10/29/2013 10:53 PM EDT)
Laszlo Sandor (10/30/2013 07:30 AM EDT)
Simon Xu (10/30/2013 08:03 AM EDT)
SeongWoo newton (10/30/2013 05:49 PM EDT)
Michael Lim (10/30/2013 08:45 PM EDT)
Milos Cubrilo & Vukasin Vucevic (10/31/2013 02:17 AM EDT)
Gale Greenlee (10/31/2013 09:43 AM EDT)
Eugene Perederey (11/01/2013 06:56 AM EDT)
Katherine Oh (11/02/2013 11:14 AM EDT)

Attention: If your name is posted here and you wish it removed please send email to the ponder@il.ibm.com.