pipeline.rb

require "bundler/inline"

gemfile(true) do
  source 'https://rubygems.org'
  gem 'concurrent-ruby-edge', require: 'concurrent-edge'
  gem 'concurrent-ruby-ext'
end

require 'concurrent/channel'

naturals = Concurrent::Channel.new(capacity: 1)
squares = Concurrent::Channel.new(capacity: 1)

Concurrent::Channel.go do
  (1..12).each do |x|
    naturals << x
  end
  naturals.close
end

Concurrent::Channel.go do
  naturals.each do |x|
    squares << x * x
  end
  squares.close
end

squares.each do |x|
  puts x
end