Hello ChucKers, I wanted to emulate something I saw on youtube once (sorry, I've lost the link), an interval keyboard where keys on the right hand play notes increasing by various intervals and keys on the left hand play notes decreasing by various intervals. I haven't any music theory and the wikipedia pages for muscial intervals are over my head. http://en.wikipedia.org/wiki/Interval_(music) http://en.wikipedia.org/wiki/List_of_musical_intervals My question is this, what should the method on Interval be called that "inverts" it (from low-to-high pitch to high-to-low pitch)? https://github.com/heuermh/lick/blob/f49ddd8285ee412f9b6c05c2ef5ba6c6cdb5432... I have learned that is not the same as an inversion, which does something else to ratios https://github.com/heuermh/lick/blob/f49ddd8285ee412f9b6c05c2ef5ba6c6cdb5432... The example is here if you want to give it a try https://github.com/heuermh/lick/blob/f49ddd8285ee412f9b6c05c2ef5ba6c6cdb5432... Cheers, michael