Older pupils can make musical "heartpacers" by using a programmable keyboard to vary the speed at which a recorded tune is played. One group of percussionists has to follow the new irregular "heartbeat", while a second group has to maintain the original pulse. This is a good introduction to some of the underlying ideas of minimalism. They can also make "regenerative" music by improvising or composing short sections that can be "implanted" into a previously composed piece. As parts of the original music "degenerate" by being played much quieter or slower, the new sounds must take their place and still sound right - the challenge being to keep the music alive during the transformation.