Mar 05 2013
A huge traffic sign adorns the highway near my home, announcing the number of fatalities on Georgia roads this year so far (it's about 150). Moving here from California, knowing this is a small state, that seems like a lot, and it is. Here is the data from 2008 for both states (rates per million …
Mar 04 2013
Sudoku puzzles are classified according to their difficulty. My old newspaper, the LA Times, did so as Gentle, Moderate, Tough, and Diabolical. Sites like Daily Sudoku have basically the same division, though the names are different (hard and very hard instead of tough and diabolical). Difficulty is determined by the techniques needed to solve the …
Mar 03 2013
A simple elimination algorithm that searches box-by-box, row or column will solve most Gentle and maybe even some Moderate puzzles. The final simple technique knocks out pretty much any remaining Gentle: Technique 4: Enumeration If the previous searches fail, try checking each square on an individual basis to see what numbers it can "see". For …
Feb 23 2013
It's possible to solve a Gentle Sudoku with only a box-by-box search technique. While this is the first technique I will normally apply, it is not the only one necessary to solve most Gentle puzzles. Sudoku has 3 rules: every 3x3 highlighted box must have 1-9, every row must have 1-9, and every column must …
Feb 22 2013
All cars have to keep themselves cool. The reason for this, as we've seen, is the inefficiency of the engine: you can't convert the heat, made in the burning of gasoline, into work without creating some waste heat. If we take the energy stored in gasoline to be the "free energy" of the chemical bonds, …
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