These tracks were composed by me and programmed in BASIC onto a Commodore 64 computer circa 1983, and
then recorded onto a cassette at that time. Lines of code looked something like this:
<track 1>E4,4; C4,8; E4,8
40 <track 2>C4,4; D4,2; E4,2
whereas for instance the E4 in line 30 indicates E on the 4th octave, and the 4 indicates hold it for 4 beats.
There was some function I can't recall to allow for multiple simultaneous tracks - which of course had to line up mathematically
in terms of harmonies and beats.