http://rubylearning.com/blog/2011/03/01/how-do-i-smell-ruby-code/

results.txt

      user     system      total        real
  9.940000   0.090000  10.030000 ( 10.038922)
  3.420000   0.000000   3.420000 (  3.429747)

smelly_code.rb

require 'rubygems'
require 'benchmark'

array = [["banana", "apple"], ["pineapple","beer"]]

Benchmark.bm do |x|
  x.report do
    1000000.times { array.collect { |sa| sa.collect(&:reverse) } }
  end
  x.report do
    1000000.times { array.collect { |sub_array| sub_array.collect { |subsub_array| subsub_array.reverse } } }
  end
end