I wrote some plucked string code for the fraktal synth and put it at preset #5. There are two plucked strings which can run simultaneously. The lower pitched string is controlled by knob #5, and the higher pitched string is controlled by knob #6. Knob #7 runs a little sequencer in combination with knob #2. I don't really like the sequencer, but I left it in becuase if knob #7 is turned all the way down, the sequencer is off. This preset plays very quietly compared to the other four. I recorded a small sample while turning knobs 5 and 6. I've tried this plucked string algorithm several times over the years, usually striving for mathematical precision in sample rate and word size, but this one sounds better. Now I realize that the sound is improved by the many imperfections, especially in the sample rate.
Here is the version 5 zip file with the source code and compiled code (CCS PCH C compiler version 3.249). I added the DSP_FIR module and made a couple little changes here and there in other modules. Feel free to use and modify, but keep it open source please.