include-test.rb

module A
  def example
    puts "A"
    super rescue nil
  end
end

module B
  def example
    puts "B"
    super rescue nil
  end
end

module C
  def example
    puts "C"
    super rescue nil
  end
end

class SingleLine
  include A, B, C
end

puts "SingleLine: "
SingleLine.new.example

class ManyLines
  include A
  include B
  include C
end

puts
puts "ManyLines: "
ManyLines.new.example

Output

SingleLine: 
A
B
C

ManyLines: 
C
B
A