#=> [9, 18, 27] a_proc[9, 1, 2, 3]         #=> [9, 18, 27] a_proc.(9, 1, 2, 3)        #=> [9, 18, 27]...a_proc.yield(9, 1, 2, 3)   #=> [9, 18, 27]
 Documentation
If this confuses you, let me explain....He breaks down how the routes.rb file doesn’t feel like Ruby and helps you build your own DSL....What are params in Ruby on Rails?...In Rails, params accompany the request, whether as a POST request or Query String.