Double flutes of different styles can be found throughout the whole world, from the far east to central Europe, as well as in the Americas: Antique Mexico and Andean regions (with the name of Marimacho).
It is an instrument that is structured in one or two tubes that produce a constant sound (or pedal), and another tube that has a pentatonic or diatonic scale. I construct them in bamboo or Jacaranda. It can be a diatonic or pentatonic scale.
Double Flute, Triple Flute