We recommend:Puzzle Contests

Kadon is sponsoring a puzzle contest on the Germany-based Bricks website, a vast collection of sliding block puzzles you can download (it arrives "zipped") to play. The contest challenge changes every month or so. Andreas Rottler is in charge. The program runs even under MSDOS, and you can also start it from Windows. Best performance is on Pentium I computers or above. Reportedly it also runs on old 386 and 486 computers—a little bit slow, but everything works. In addition you need a mouse, a graphic card and a color monitor. Sorry, there are no Mac, Unix or Linux versions. Winners receive selected Kadon gamepuzzles as prizes. Visit the Bricks site to see the current contest and deadline for entries.


Pentomino Competitions
A classroom teacher, Odette De Meulemeester, and her students at the school, K.S.O. Glorieux Ronse (Belgium), in 1999 created a delightful website with diverse pentomino competitions that attracted an international audience of pentomino lovers. (Select your preferred language.) An early challenge was to enclose the largest area (maximum, 175) on a cube. See a sample at left. Their Records page has names of top solvers. The competitions ran for 50 episodes, ending with a special 50 design by Kate Jones. The winning design by Peter Jeuken earned him the award of the special "50" edition of our Poly-5 puzzle. Although Odette retired in 2011, the students continue wonderfully to tend and expand the site as part of their math and technological education, under director Eddy Moreau. Have fun trying your hand at their elegant challenges. Kate also contributed Challenge No. 34, with minimum and maximum perimeters based on the cool cover design of the Quintillions booklet.

Recently added pentomino challenges are here:




Kadon contests
Other contests of our own are featured, sometimes hidden, throughout the gamepuzzles website. Some award prizes, some only fame. Most are also listed in our Site Features page here:   Other Amusements. The following challenges are still unsolved and open to the world (links open in new window):
  • Arc Angles—form one closed matched loop of all 25 tiles, with the minimum enclosed area.
  • The 25-Holes Challenge— fit thirteen Vee-21 tiles (V-trominoes) rigidly into their 8x8 tray with no slipping or sliding. New solution wins a silver dollar (up to 25 winners). The 37 and 40 holes are also still unsolved and will win a prize.
  • Cornucopia—form progressively longer rectangles with a 17-piece subset of Sextillions in 15 steps. New solutions win fame and a small prize.
  • Hopscotch—form 7 congruent areas of 12 unit squares. A new shape (or proof there are no others) wins you a nice prize.
  • The Octo Clock—arrange 8 numbers as a clock face to meet goals.
  • The Mini-Quiz series—we've published 8 so far, all still open. No one has fully solved Quiz No. 6. We are curious and curiouser...
  • Rhombiominoes—connect all pieces of same color; new solutions win prize.
  • Poly-5 Perimeter—fill the border with a maximum of pentominoes. Improve on our results and win a prize.
  • Ten-Yen Enclosure—surround one color with the other two, in the smallest perimeter.
  • Triangule-8 Sprouts—form 25 sprouts or prove that 24 is the maximum possible.
  • Vee-21, the Three-Color Problem—the search for more solutions of maximum color separation.



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