Another version of split random

split_random.rb

class Array 
  # split array into groups up to n items, randomly choosing the size.  
  def split_random(n)
    size == 0 ? self : (size == 1 ? [self] : self[1..-1].reduce([[self[0]]]){|ll, elt| (rand(n)==(n-1) || ll[-1].size==n) ? ll + [[elt]] : ll[0..-2] + [ll[-1] +[elt]]}) 
  end
end