factory_method.rb

class Pizza
  def initialize(&factory)
    @factory = factory
  end

  def bake
    @factory.call
  end
end

a = Pizza.new { puts 'This is a Cheese Pizza' }
a.bake #=> Making A Regular Cheese Pizza

b = Pizza.new { puts 'This is a Pepperoni Pizza' }
b.bake #=> Making a Pepperoni Pizza

c = Pizza.new { puts 'This is a Deluxe Pizza' }
c.bake #=> Making a Deluxe Pizza


system("stty raw -echo") #=> Raw mode, no echo
char = STDIN.getc
until char == 113
case char
  when 97
    a.bake
  when 98
    b.bake
  when 99
    c.bake
  when 113

  else
  "error"
end
char = STDIN.getc
end
system("stty -raw echo") #=> Reset terminal mode