A fun new online interactive musical experience between humans and computer gives us a good example of machine learning. The experimental gadget is called A.I. Duet and it calls Tone.js which allows you to play a question-answer game with the computer on a MIDI keyboard. The machine listens to you play, then replies to you. In terms of music, nothing extraordinary so far. In terms of programming, what makes this example interesting is that the algorithm knows nothing of musical theory, nothing of musical notation or rhythm, at least nothing in the form of rules as we would imagine. Its reference is some musical examples which the programmer has given it as models to build its neural networks. From what it has learned in analyzing this material, the computer tries to elaborate a sequence of sounds whose rhythm and melody is a response or a logical musical progression to that which you just played.

Not earth-shattering in itself, but this little game illustrates simply and well how artificial intelligence is progressing.
Incidentally, it also shows how far there is to go.

This experience is part of the vast Magenta open source code neural network project from Google. The three first letters of the name come from Music and Art Generation with Machine Intelligence.