The compositions each have a musical core, a "genome", that gradually becomes more complex.
He gradually added more complex combinations, building on the earlier steps.
"Our productions have gradually become more complex in terms of dramatic development and artistic collaboration," said Ms. Santana.
Scored for a solo percussionist playing five tuned drums, it begins as a purely visceral, steady barrage and gradually grows more complex, not only in its increasingly dense rhythmic counterpoint and subtle melodies but also in the constantly shifting dynamic and tempo relationships between the drummer's hands.
"I went to the audition, and I loved the freedom of hip-hop so much that it was like, 'O.K., I can see I'm not going back to my concert world!' " Ms. Gibson gradually developed more complex choreography for Ms. Blige, and Mr. Combs, an executive at Ms. Blige's label at the time, noticed.
Over the following few years, that battle gradually grew more complex, as the home saw the adoption of a new generation of HDTV sets, game consoles, set-top boxes and DVR options.
These feedforward pathways are pictured as connected hierarchies of areas designed to construct the visual image gradually — adding more complex features as one marches through successive levels of the hierarchy.
All participants received an exercise protocol in which the exercises gradually became more complex (Additional file 1; Figure 2).
