The Quilcom Mystery synthesiser was designed to explore a specific type of technique whereby an additive synth (with sub) can have the amplitude of each partial modulated by its own independent polyphonic LFO. Many settings can be randomised manually or via a trigger generator, and there are two identical sound generators for nice stereo effects and a fuller sound.
The technique seems to be most useful for pad and soundscape making, so that’s what the presets focus on.