Tonalis is a new concept in music software. It performs four part harmonisation in the common practise period style. Start by entering a melody using the piano keyboard. Press harmonise and the app will automatically generate alto, tenor, and bass parts. Progressions are optimised to minimise the movement of inner parts and so the bass line is in contrary motion to the melody. Tonalis uses techniques gleaned from various sources including the book “Theory of Harmony” by Arnold Schoenberg. Using this software, anyone can instantly produce original compositions. Choose from a selection of instruments and playback your compositions. Export the score as an image or a MIDI file.