"Pianissimo" [mp3 moved to Bandcamp]
The first theme is modular patch, forget how I did it; there was a lot of routing and interconnection among modules (not saved). The gritty percussive slaps are probably the LFO doing something to the signal.
The high-pitched whistling-like theme is a triangle wave FM-ing a sine with ADSR modulating both the program and carrier. It was as punchy as an icepick through the temple so I softened it with a slight convolution reverb (small room).
Often the tunes I write start as MIDI prompts to hear what a patch is doing and end up becoming real melodies. That was the case here, so I played the same MIDI notes with a piano (sampler) to hear the tune without all the synth distortion. The tune is then tweaked in the piano roll to add pauses, discords, and accents that a live player might have.
Then the synth themes come back in, with the piano bass line changed to a latin jazz sort of thing for some counterpoint to end the song.