own flatten

gistfile1.txt

def my_flatten(s)
  s.inject([]) do |arr, el|
    el.respond_to?(:to_ary) ? my_flatten(arr+el) : arr.push(el)
  end
end

samples = [
            [[[2,3],[5,6,7],[[8,9],10],11,12]],
            [1,2,[3],4],
            [:foo, 'bar', 42, [{baz: 23}]]
          ]
          
samples.all?{ |s| my_flatten(s) == s.flatten } || raise
puts 'Done ;-)'