From: Frank Fischer <frank.fischer@...>
Date: 2009-06-16T16:20:10+09:00
Subject: Re: [QUIZ] Matrix Rotator (#209)

Here's my solution:

class Matrix
    def self.rotate( mat )
        mat = mat.map{|r| r.reverse}
        mat.first.zip(*mat[1..-1])
    end
end

Again, it works by reversing the elements in each row and transposing the
matrix.