3 versions of the system

one version of the system that strictly plays only with the forced choices

one version that generates substitutions only at the pauses and double hits, when no pauses and double hits, it follows the lead exactly

other version, that generates substitutions only at the pauses and double hits, when no pauses and double hits, that introduces random variable note at any position(1st and last position only), generates substitutions and follows

other version that substitutes at pauses, double hits and also at the non accented positions, selection of choices is random.