Organic Engines derives its themes from sources in the natural world. The structures follow no set form, but rather resonate with the composer's experience of the patterns of water flowing, or time passing, or hillsides marching across an impossibly blue horizon.

Touch Wood overlays a variety of sounds and rhythms, including kalimba patterns, Ethiopian folk music, bird cries, the slapping of windblown tree branches, the fluting of wind blowing over holes in rock, and the underlying energy of heavy metal music.

Murmurs is an ode to a best friend's irregular heartbeat, and uses that fluttering pulse in the marimbas as its basic theme and ostinato, while their speech patterns and vocal tone are evoked by the cello.

The dozens of motives that form the tonal collage of Cicadas were recorded by the composer on the eastern coastal forests of New Zealand's North Island. There, the cicadas are so numerous to create a massive wall of sound to the naked ear, but when a microphone is applied to each separate bush, a different collection of sounds emerges. Cicadas seem to form small clumps that follow tonally related patterns, each with a guiding soloist, which changes slightly in key and rhythm from bush to bush. The movement's opening motive is a close approximation of the most typical cicada song, and is soon joined by many variations from different soloists. The lyrical passage in the middle is simply an elongated patchwork of songs strung together and melodically synthesized. The ending is the actual death rattle of a huge cicada being caught by an even huger spider.