Infinite Search Space
History

The story so far.

Infinite Search Space ran four contests in 2011 and 2012. Each posted one hard problem, gave players months to search for better answers, and ranked them on a live leaderboard. Here's how it started, what was played, who won, and where the results ended up.

Before ISS

Learning from the best

ISS's founder, Neil Brewer, had been entering Al Zimmermann's programming contests since 2005: Primal Squares, Circle Packing, Searchin' for Kurchan, Words Search, and later Point Packing, Son of Darts, Retaining Water (10th place) and Topswops. He also entered every puzzle on James J. Youlton Jr's Virtual Source contest site, and helped James put the contests together.

Those contests had a simple, addictive shape: one beautiful problem, months to chip away at it, and a leaderboard that counted every improvement. ISS was built to run contests the same way.

2011Opening

A Dell in the garage

The original site ran out of Neil's garage, on an old Dell tower PC: Fedora 15, a 250 GB hard drive, 2 GB of RAM kindly donated by Ed Mertensotto, and a Drupal site on top. Its About page was honest about it:

“Not exactly the beast you would want for a server, but it'll do. I'll make sure of it.”
ISS About page, 2011

The rules were relaxed from day one. Nobody had to show their code, only their answers: “Work it out on paper, write a program, or consult a psychic, it's up to you.” Play was “mostly for bragging rights”.

The prizes were homemade too. Neil's father was taking a graphics class at a local college for fun when the site was being built. One of his first assignments was to design and screen-print a simple logo, so he designed the ISS infinity logo and printed T-shirts for the winners. It's the same logo at the top of this page.

Neil added one detail of his own: the thin break across the middle of each loop. It's an infinity sign with a crack in it, and it tells the truth about every puzzle on this site. None of them is really infinite. Each has a last possibility somewhere, and a machine patient enough to try them all would eventually find the perfect answer. But that patience would outlast us all by a very long way. The search space is finite, but our time is far more so. So we search cleverly instead.



Plant N trees at whole-number coordinates to make as many lines of exactly four trees as possible, for every N from 11 to 60. A single line with five or more trees made the entry invalid. Each size scored your result divided by the best anyone found, so a perfect score was 50. The scorer used arbitrary-precision arithmetic, so coordinates could be as large as players liked.

  • 69 players
  • Ended on Christmas Day
  1. WinnerIl Brigante Pennastorta
    49.5643
  2. 2ndKendrick Boyd
    49.0535
  3. 3rdJim Gillogly
    48.8945

The winner played under a pseudonym: Il brigante Pennastorta is the Italian title of Otfried Preußler's children's book The Robber Hotzenplotz. In January 2012, Natalya Makarova suggested a follow-up mini-contest, posted by Dmitry Kamenetsky: fit the best orchards onto the smallest possible grids.



The classic tile-clearing puzzle: remove groups of same-coloured tiles, let the rest fall, and score more for bigger groups. Players searched for the best sequence of moves on 25 fixed boards. The prizes included signed copies of Dave Phillips's maze books, donated for the contest.

  1. WinnerWes Sampson
  2. 2ndMarcos Donnantuoni
  3. 3rdDmitry Kamenetsky
“Brute force is a bit moot in any contest on a website called (only slightly inaccurately) infinite search space.”


In 2009, William Gasarch challenged the world to colour a 17×17 grid with four colours so that no rectangle has all four corners the same colour. When that was finally solved in February 2012, Dmitry Kamenetsky asked the obvious next question: what about more colours? He and Neil turned it into ISS's third contest. For every number of colours from 1 to 21, find the largest square grid you can colour with no single-colour rectangle.

  1. WinnerAlex Chernov

The contest's discussions produced real mathematics. Gasarch and his co-authors cite it in their paper on the problem, and use two results from its forums: Tom Sirgedas's four-colouring of a 21×12 grid, and Quimey Vivas's proof for grids of c²×c² when c is prime.



A prime-number search that drew more than 60 players and one of the tightest finishes ISS ever saw. Two players reached a perfect 50.000, and three more were within a twentieth of a point.

  1. Joint winnerDmitry Kamenetsky
    50.0000
  2. Joint winnerAlex Chernov
    50.0000
  3. NextRobert Gerbicz, Wes Sampson & Herbert Kociemba
    49.9956
2013The quiet years

The lights go out

After Prime Sums, the site went quiet. The last snapshots of the original ISS date from the spring of 2013. A teaser for the next contest, “Jelly Beans!”, was posted after SameGame, but no Jelly Beans contest appears in the archive. Maybe it's still waiting.

Still cited

Where the contests left a mark

Thank you

The people who made it

The original About page thanked these people “for their advice, guidance and inspiration in putting these contests and this web site together”:

And every player who searched, from the champions at the top of the leaderboard to the one who entered as “Rita the dog”.

2026Relaunch

The search continues

Infinite Search Space is coming back, with new contests and a classic room where the old records can be challenged again. Back to the home page →