reduce_methods.rb

class App
  def plus1(n)
    n + 1
  end
  
  def double(n)
    n * 2
  end
  
  def triple(n)
    [n, n, n]
  end
  
  def run(n)
    [
      :plus1,
      :double,
      :double,
      :triple,
    ].reduce(n, &call)
  end
  
  def apply(x, f)
    method(f).(x)
  end
  
  def call
    method(:apply)
  end
end

result = App.new.run(10)

p result