Some composers have wicked symphony’s in his mind. And sometimes that minds eye involves dueling piano’s… but when its written, its only for one instrument. Generally then cheats are used, perhaps while one is rolling off, the next set of notes are hit. Or perhaps the piece is subdivided into doable pieces. And occasionally a pianist works on their span and produces some amazing music. Here is an example of Rachmaninoff in which they decided it was a spam best done… with assistance…
