From: Todd Benson <caduceass@...>
Date: 2009-06-16T04:40:53+09:00
Subject: Re: [QUIZ] Matrix Rotator (#209)

On Mon, Jun 15, 2009 at 4:22 AM, Robert Dober<robert.dober@gmail.com> wrote:
> I should not have posted my bad, yet Todd you forget it is Ruby you
> should put the blame on ;)
> But I guess it is not that simple anyway, puuuh.
> R.

I don't want to hijack the thread, but since my venting is off topic,
it will probably get lost in the noise anyhow.  Solving a cube (of any
number of pieces) is mostly working backwards from a solved state.  A
good transformation algorithm is handy.  Maybe that should be another
quiz :)

I tried a mathematical transformation for this quiz so that it could
be useful for something other than a quarter turn.  Didn't work.  For
those more inclined to "make it so", it's an inverse matrix in front
of a position matrix.  What's funny about the extra dimension required
fascinates me.  I get the math, but why do we need singularity (a
bunch of 1's) on that final dimension?