Erasable Games Weblog

(Sudoku in words and pictures)

Archive for February, 2008

Eye Chart Sudoku

Monday, February 25th, 2008

Eye Chart Sudoku

Have you ever been to the Eye Doctor (Optician, Opthalmic Dispenser) and got tested for your visual acuity and thought: “This test is too easy!” ? I have. The result is this cartoon. I heartily recommend it to all who have to get their vision checked. Try to talk your doctor into using this chart rather than his. You may both be surprised at the results. Consider it a Vision Quest.

Spider Sudoku

Sunday, February 17th, 2008

Spider Sudoku

While escorting a spider out to the back yard, I mused about how spiders might solve Sudoku puzzles. This is the result. It relates to the party game of Twister patented by Charles F. Foley and Neil W. Rabens in 1966 and originally sold in the United States by Milton Bradley Company.

According to Torsten Sillke, The original inventor, Reyn Guyer, designed a Polka Dot Mat For store display purposes, but later converted it into a game and called it “Pretzel”. Currently, Hasbro Toys which took over Milton Bradley in 1984 sells the game.

I imagine that Spiders “instinctively” solve the puzzle, given the various starting numbers by transitioning from all instances of one value ( such as an 8 ) to all instances of the next value chosen. This is rather unlike humans, who use logic and solve by rows, columns and blocks.

The underlying (!) puzzle is considered hard, but may be made easier by taking the spider’s hints.

Ripple Effect Sudoku

Monday, February 4th, 2008

Ripple Effect Sudoku

This Puzzle uses various sized grids to fit sets of pentominos within. I’ve chosen a 9×9 grid. I think the name, Ripple Effect is suggestive of bigger integers making a bigger splash given their unneighborliness in the rule set. There are no tip sheets as yet, although a strategy may be like that of Paint By Numbers, where you have to account for not only where candidate numbers could be, but also where they cannot be. Ripple Effect was created by Nikoli in 1998.

There are some sites with Ripple Effect Puzzles:

You, an online puzzle site with free and paid memberships. Getting a free membership is a chore, if not impossible. The form decided my email address was already in use and rejected its association with a new userid! Clicking on Account details made no impression on the script.

Online Puzzle Ripple Effect has multiple puzzles of sizes 8 x 8, 10 x 10, 18 x 10 and 24 x 14.

Ewe Weidemann’s Sudoku Variants Page.
This site has a huge number of Sudoku and other Puzzle variants well organized, although mostly one example of each kind.

I may have to acquire some Nikoli published puzzle books on this variant.