RNG music bot

This is a bot which generates random chord progressions following modern western music rules.

Each progression has 4 chords, and will starts with I and finish with either IV or V

For the 2 missing chords, the bot generates 2 random numbers between 1 and 6 and will fill in the blanks with one of the resulting chords (I , ii , iii , IV , V , vi)

There's also 3 possible drum track, each one has a 1/3 chance of changing state (playing or not playing) with each chord.

You may download the source code which is compatible with Game Maker Studio: 2, and are free to use it in any project you want, paid or no. (just Make sure you credit me)