  This paper addresses a question about music cognition: how do we derive
polymetric structures. A preference rule system is presented which is
implemented into a drum computer. The preference rule system allows inferring
local polymetric structures, like two-over-three and three-over-two. By
analyzing the micro-timing of West African percussion music a timing pattern
consisting of six pulses was discovered. It integrates binary and ternary
rhythmic feels. The presented drum computer integrates the discovered
superimposed polymetric swing (timing and velocity) appropriate to the rhythmic
sequence the user inputs. For binary sequences, the amount of binary swing is
increased and for ternary sequences, the ternary swing is increased.
